It depends on which version of 'pack the courts' you mean. Increasing the numbers just leads to an arms race that achieves little beyond a brief window where the presidents side has more justices, before the next president just increases the number again to swing it their way. Alternatively, telling all the ageing justices of your persuasion to get out while you can replace them with younger people makes more sense, and he and all previous Dem presidents absolutely should have done so, and not doing so is not smart. I'm not sure it's so much them supporting the current state as thinking their opponents will play fair, which is even more colossally stupid.

I hope that at no point have I suggested the Democrats or Biden are a good choice, just that they're a less immediately terrible choice than the Republicans and trump. The Felon has made it clear that he will enthusiastically support and extend all the worst positions the Dems have taken and also want to be a dictator. Neither is a good choice, but one is worse.