Although young-earth sources do regularly cite old-earth sources, the citations are rarely honest. First, the source being cited is routinely not represented accurately. Michael Roberts slogged through over 100 of Woodmorappe’s citations of supposedly problematic radiometric dates without finding a single valid problem. Creation Moments cited an article claiming that it showed that the transition from toothed ancestors to baleen whales was a problem. But the article actually stated that the transition had been a problem before the finding of the transitional fossil that the article was about. Secondly, there is no honest effort to thoroughly research the old-earth literature to test the claims; it’s merely cherry-picking what seems suitable for distorting out of context into apparent support for a young-earth model. Unless you only rely on the young-earth literature, you will quickly see that creation science is merely propaganda and does not actually reflect a serious effort to understand how the universe works. This is why, for example, that no oil or gas or other geological resources have ever been found by using young-earth models. They don’t even tell you where to look - there is no consistent framework that could be used to identify what layers are likely to be productive. Even the many young-earthers working in the oil industry use old-earth models when it comes to actually finding anything. Every time you use oil or gas or plastic or nylon or metal or brick or concrete or other geologically-derived resources, you are benefitting form the effectiveness of old-earth models.
Although there are some tradeoffs between intensity and time, the examples already mentioned show that they are not inherently equal. For example, it is true that decaying organic material can be broken down into oil or gas somewhat faster if it is under higher heat and/or pressure. But heat and pressure affect other things as well. It’s possible to determine amounts of heat and pressure experienced by rock layers, based on the types of minerals present and the degree of alteration of the materials present.
The effects of floods, tsunamis, and other proposed agents for flood geology models can be observed and compared to the geologic record. By the late 1700’s, it was clear that sedimentary rock layers generally matched the slowly depositing sand and mud that can be found today, though with occasional layers that seemed different. Even earlier, it was clear that the series of layers did not match what could be produced by a single brief, massive flood. (The idea of layers being slowly produced by a gradually retreating once-global ocean took longer to refute.) Excessive resistance to catastrophic causes and excessive invoking of catastrophic causes can be found at various points in the history of geology; any claim must be tested against the evidence. For example, the erosion of canyons into the edge of the continental shelves cannot be caused by a global flood. They reflect river erosion during lowered sea level (sometimes much lower, in the case of those around the Mediterranean), coupled with mass wasting events (such as landslides).
The inselbergs and monandnocks have experienced lots of erosion, just as the surrounding areas have; because of being harder, they have eroded more slowly. The ridges in the county I live in, and several of the mountains in this part of the state are mostly areas rich in quartz, and thus have eroded more slowly. A smaller-scale, much faster example comes form the bricks along the edge f the building where I work. The sand and gravel in the bricks are tending to stick out as the baked clay erodes away where the brick gets all the drips off the roof hitting it. It’s not just hardness (and hardness is scratch- or dent-resistance, not breakability). Chemical resistance may be more important. Soapstone tends to be left on the surface as boulders while the surrounding rock erodes away. It’s largely talc, with a hardness of 1, but it’s chemically so resistant that it has been used for lab countertops. Quartz is both chemically and physically resistant, so it holds up well in most environments. I’m in the southeastern US, so there’s plenty of hot and wet weather, making chemical breakdown of rock very important. Drier areas have different patterns of rock types being left behind.
If the erosional remnants were produced by a global flood, such patterns should not be found.
There is confusion in the claims about quartzite being carried away form the Rocky Mountains, so I’m not certain just what the actual evidence is. Sand is mostly quartz, so the reference to softer rocks is inaccurate. Such inaccuracy in irrelevant details does not inspire confidence in the geological merit of the argument. I would guess that either pebbles of quartzite eroded from the Rocky Mountains or quartzite containing sand grains that eroded from the Rocky Mountains might have been what was actually found. An important detail omitted is how the pebbles or sand can be identified as coming from the Rockies. First, that would inform the range of possible geological models. Which layer does it come from and when was it first exposed and available for erosion? Most of the mountain ranges west of the Rockies are rather young, geologically. [Note: these considerations would apply to assessing possible young-earth or old-earth models.] Second, many of the features that would be useful for identifying the origin of pebbles or grains reflect an old earth, such as radiometric dating (if it were sped up, there should not be distinctive dates for different layers, but rather a big blur) or the degree of metamorphic alteration. Pebbles can wash downstream without exceptionally high water speeds. The Missoula floods certainly carried some rock downstream, but so does the ordinary flow of the Snake River, for example.
Comparison of geological claims from young-earth sources versus the actual geologic evidence gives no reason to trust young-earth claims. If there is enough detail, I can look it up and find out precisely what the evidence is, but experience shows that “Here’s evidence for a young earth” and “Here’s a photo of Bigfoot and Elvis riding the Loch Ness Monster” have similar promise of turning out to be authentic.