I don't think playing a cranky racist character means you are racist, so the Plinkett stuff is pretty irrelevant. The Plinkett writing will take any excuse to make lazy jokes that are designed to be offensive but it seems like the joke is really on the character, who is portrayed as a creepy, lonely, dying, slothful, failure of a person.
The Ghostbusters 2016 discourse was in fact very toxic and overheated and hostile towards people who just say they didn't like the film, and at the risk of catching heat myself, I actually agree with their complaint. Let's not pretend that Hollywood is above playing up having an all-female cast and trying to use that simple fact to deflect criticism. Hell, I know I would at least TRY to if someone came after a very expensive thing I made that starred all women. "You don't like it because you're sexist" would probably be the first thing I said. It's an easy win because it puts the critics on notice that negative talk about your property is going to be put into a box that's going to be hard to get out of. This is not to deny that sexist comments did exist, but actually if you watch the video, a good chunk of time is spent trying to analyze how much of that commentary actually existed and what impact it had vs. the well-circulated PR statements crowing about how the film was under attack.
That leaves Rich's rant, in which he calls Trump an "ex reality star orangutan" and says he didn't understand the point of the women's March that occurred before Trump took office. It's very out of touch. I marched in it myself. The world wanted to let Trump know we will resist his attempts to subjugate women, and we will not forget his indiscretions towards women. Rich think that was premature at the time as he wasn't in office yet. I can imagine thinking that way if you're breezily watching all this with no skin in the game, but I don't myself. Still, he's allowed to be wrong so long as he doesn't actually support Trump's sexist and racist policies and statements, and I don't think he does.
So, no, it's not time to cancel them. It's the same time it always was, which means it's time to either take or leave RLM's content according to whether it has any use for you, whether edgy jokes do it for you, and whether you find value in content created by un-woke, out of touch, but probably harmless middle aged white guys.
I don't. (Except when they are shitting on Star Wars. Because there hasn't been a good Star Wars movie in 39 years.) But I'm not going to come for anyone who does.