As Scott Adams (of Dilbert fame) likes to point out, accusing others of hypocrisy is one of the stupidest, least persuasive things a person can do.
The reason is that all of us are hypocrites in one way or another. You might as well accuse someone you don’t like of being human. But that would be useless, wouldn’t it? Being human is normal and it doesn’t mean (much less prove) that the person you dislike has beliefs and opinions that are wrong.
Still, in political and legal matters, double standards (a type of hypocrisy) are validly concerning. A republic cannot operate when the generally-accepted rules of behavior apply in one way to one political faction and in a different way to another. Similarly, there can be no rule of law when legal prosecution goes after one person or group but not another for the same behavior.
Do you see the problem? It is practical in nature, not theoretical.
This is the context in which to understand the current impeachment trial. See this montage presented in the Senate today to grasp that the Democrat impeachment managers are seeking to criminalize behavior by Donald Trump that their own faction is guilty of:
It is not a question of hypocrisy. Because the impeachment trial is real, the issue at hand is one of wasting time and attention on trivialities. The consequences down the road will not be trivial.