I hate that I have to preface all this with the fact that I'm a liberal voting Canadian:
I think dismissing the political part of it as whining isnt fair. He did have a point about the number of openly conservative celebrities vs openly democratic celebrities & how there are some hiding their views to not face backlash from the public. Also seeing how Roseanne has been met by those with differing political viewpoints, ABC being owned by Disney (likely don't want to associate with a Pro trump POV)...etc
It may not have been the sole purpose but you can't deny it plays a big part for corporate image.
I believe it had weaker numbers in the 18-49 key demographic than ABC's other sitcoms at the time of its original cancellation (those shows now have weaker numbers in that demo though): Modern Family,
black-ish, and The Goldbergs. That along with Allen's impending pay raise = ABC not seeing any profitability reason to keep it going. If a show brings in eyeballs in that magical 18-49 demographic, a network isn't going to just cancel it.
And let's not act like 6 seasons wasn't a decent length for a sitcom--it was.
I still believe this is an example of Tim Allen (again, I am a fan--I loved Home Improvement growing up, Galaxy Quest is one of my favorite movies, and I thoroughly enjoy the Toy Story series) having some sour grapes about losing out on a pay increase, and chose to act like some sort of put-upon victim. From all accounts I've read/seen the show wasn't really all that political in nature anyway, so I see that as another reason to label it as whining.
An entertainer's politics don't matter to me though, so even though I've generally been a fan of his work that's why I was disappointed to see it. I mean I like Clint Eastwood's directorial efforts, could not care less about what he thinks about politics (just another example).
Now in the end I'm happy it came back for those who enjoyed the show and were a fan of it. Everyone deserves to have something they like to watch on TV.