Well as a user of the site I’m pretty happy with the payware now being added.
I use payware scenery quite a lot for my automatically generated flight plans. I prefer freeware scenery as my routes change quite a lot but when no freeware is available I don’t mind looking at a payware alternative if it’s not too expensive. I’m happy for them to point it out for me, all in one search hit.
With regards to the legal stuff, I do practice law. Giving it the quick glance over as mentioned here, it mostly just disclaims them from copyright infringement by users but also modders modding your mods; recycling your work into something new or better. Say someone uses your runway texture mod to enhance an airport, you can not enforce original copyright to it. I really don’t see any wrong doing here. The topic author mostly seems to be worried about their ability to change their terms of use and how they may some day ask money for someone else’s product but I can’t see the public agreeing to such PR-disaster really.
I don’t think this is a slowly enrolling scheme but probably more the outcome of them learning from their early operations, growing so big so fast and experiencing some minor legal claims left and right that they’re now ironing out, making sure everyone know what to expect and formally establishing their freeware ambitions, from and for the community.