It's more like the congress exercised there constitution power to do fuck all if they wanted. Just cause it's a shitty thing doesn't make it un-constitution. What happened to Obama was his party didn't have the votes to approve someone so it didn't happen that's it.
If they hold hearing for a 45 nominee before the election, they prove they were acting in bad faith. The expectation is that the president gets to appoint judges during his term, unless there is a reason to deny the nominee. By denying that they challenge the power of the executive branch. I.e. Does the president only get to pick a judge if the senate is a majority from the same party?
It's a bad faith enforcement of the constitution. In democracies like the US, precedents are as powerful as laws. This was not literally breaking any laws, but this was as bad as breaking a law.
Doing things that are so obviously destructive to the whole institution of government that the Founders thought it wasn't worth writing down in the era of quill pens on sheepskins, because they couldn't imagine anyone being evil enough to do it? Yes, that's what bad faith is. It's things you can technically create a justification for that contradict all decency.
Yes and there is tons of case law on what the Senate actually needs to do and the result is "fuck all". The Federal government is designed to gridlock rather then forcing things to happen.
No, what happened is that Mitch McConnell refused to even allow a vote, and even Republican senators wouldn't have been able to vote for the centrist proposed by Obama.