Is it necessary to provide a rebuttal to so-called reformist/progressive Muslims? Not really. If you try to engage in debate with them, it is a fruitless exercise because they have no usul. They have no clear, explicit principles they use to derive all the strange, divergent opinions they come up with. So if you try to hold them to something, they quickly pivot to something else and the conversation goes no where. I speak from experience… A lot of face-palming experience…
But you don’t need to engage reformist/progressive Muslims in order to completely debunk everything they stand for. You do this by attacking the root of their ideology: liberal, modernist thought. That is something worth spending your time on. Consider this example.
Reformists make a big deal about hijab and gender separation in general and how it is oppressive, patriarchal, etc., etc. The more sophisticated reformists will cherry pick from different historical texts and trot out a generous helping of “maqasid-based reasoning” to make their case. Some people might certainly want to get their hands dirty and point out all the things they get wrong about the texts and their bastardization of maqasid and maslaha, etc., and this is an admirable endeavor in its own right. But unfortunately the reformists will just shift the argument and use another set of texts and another set of arguments. Like fighting a mythological Hydra: You cut off one head and two more grow in its place.
A more efficient route is to just stab the Hydra in the heart by critiquing the modernist assumptions about dress, oppression, patriarchy, gender roles, etc. By debunking these notions, you take the wind out of the reformist’s sails. And since the vast majority of these reformists are such shallow thinkers, they usually haven’t even reflected on the roots of their own ideology to see if they are sound or hold up to the least amount of scrutiny. It’s quite sad actually that people destroy their iman and try to change the religion on the basis of such flimsy philosophies that are relevant only because they’re trendy at this point in time, but otherwise have no redeeming intellectual or moral quality.