I'm of the personal opinion that it's quite reasonable for the creators to want attribution in case you manage to build a "successful product" off their work. The fact that it's a new or different license is a much smaller thing.
A lot of open source, copyleft things already have attribution clauses. You're allowed commerical use of someone else's work already, regardless of scale. Attribution is a very benign ask.
You speak as if "license proliferation" is actually a problem.
But is it really?
Sure, it may make some licenses incompatible with each other, but that's basically equivalent to whining about somebody releasing their code in GPL and it can't be used in a project that uses MIT...
And your argument that the terms are "less understood" really doesn't matter. It's not like people know the Common Public Attribution License in and out either. (I'm going to argue that 99% devs don't even know the GPL well.) Poor drafting could be an issue, but I don't think this is the case here.
And on an ideological standpoint, I don't think people should be shamed into releasing their code under terms they aren't 100% comfortable with.
I personally have no (or at least little) problem with attribution. As you say, quite a few licenses have some degree of attribution required. There's even a whole dedicated (and OSI approved) license who's raison d'être is about attribution:
https://en.wikipedia.org/wiki/Common_Public_Attribution_Lice...
What I'm saying, if I'm saying anything at all, is that it might have been better to pick one of these existing licenses that has some attribution requirement, rather than adding to the license proliferation problem.