I'm still not convinced of that. It's not necessarily accurate to say that a UASF can't be contentious. I'm of the view that any time one "side" is trying to force the hand of another "side", then it's contentious. Bitcoin depends on users, devs and miners working in unison. Power struggles aren't conducive to that aim.
That’s the ideal path, but men/women being political creatures, never forget that Jihan Wu, and his friends used signalling as a political tool to hold Segwit because it would disable cover ASIC-Boost.
I believe without BIP148, Segwit would be delayed, and delayed, and delayed. Plus this is what decentralized governance is. There will be discord.