In my opinion, this is not a reasonable request. Someone like Dennis Venema whose expertise is in genetics shouldn’t need to respond to philosophical / theological questions. It’s out of his realm of expertise, unless I’m mistaken and he has an MDiv or ThD somewhere in his CV that I haven’t ferreted out. Your expectation assumes that all thinking, committed Christians (almost by definition, must) come down unequivocally one way or another in these matters of God’s sovereignty; it assumes that agnosticism in such matters is not an option for the serious follower of Jesus. This is not the case.
A better request (again, imho, and I do mean the “h” part here) might be that BioLogos would host a “five views” sort of blog-dialogue about these matters. (Perhaps they have already done so.) This would allow the exploration of these matters for those like you who are interested.
By the way, “heresy” used in the colloquial sense is a relative term; there are Christian traditions (yea, even Protestant ones) that find Calvinism (“Calvinism,” I could say, as typically understood) to be heretical, as I’m sure you know.