Everyone is applauding this because they hate Trump, but take a step back and see the bigger picture. This could backfire in serious ways, and it plays to Trump's base's narrative that the mainstream media and tech giants are colluding to silence conservatives (and maybe there could even be some truth to that.) I know the Valley is an echo chamber, so obviously no one is going to ever realize this.
POTUS has the most popular (and currently most controversial - note, that's _controversial_ not _extreme_ or some other morph) so it's easy to see why Twitter are on top of it. Other blue-checked accounts, whilst more "important" than unverified, just simply don't compare to the importance and prevalance of POTUS' account.
Update: data https://quillette.com/2019/02/12/it-isnt-your-imagination-tw...
Update: admission https://www.vox.com/2018/9/14/17857622/twitter-liberal-emplo...
I'm not being facetious. Isn't this something the right is actually proud of? I mean, they actually boast about not being "politically correct" (something the rest of the western world calls "common decency").
So look at it this way: are the things that conservatives say outside the bounds of common decency of the 1980s? 1950s? 1930s? Then ask if the kind of things that left-leaning users say are outside the bounds of common decency of the 1980s, 1950s, 1930s.
You say that political correctness is just common decency. Your grandparents probably had a different standard for common decency in their day.
The overall trend is that justice and respect for human dignity has steadily, undeniably, increased over the last several hundred years. Therefore, generally speaking, I would say that yes, a modern 30-something has more "decency" than one of 50, 75 or 100 years ago.
To be totally clear, I don't fault my grandparents or other people that are products of these eras. They aren't necessarily bad people. And certainly, the measure of "common decency" would, of course, be different then.
I just can't wrap my head around longing for a time when society was more constrained/repressive/intolerant. Yes, there are things I think were better in the past, but they are the exception.
(side note: this is not to say I don't think political correctness can go too far, it certainly can. There are exceptions to everything).