In that context the failures of the US (as it is de-facto the standard-bearer of political liberalism in a broad sense), have real influence.
When the Chinese look around the world and they see the state of the US on imprisonment, racial conflict, failure during the current covid crisis and so on, this strengthens the domestic control of the party and the alternative autocratic system the government is advocating.
And as far as communications infrastructure is concerned it's relevant too. In countries like Germany or Eastern Europe in particular the behaviour of espionage among allies over recent years has created an atmosphere of "well everyone is spying on us anyway" substantially weakening the case against Huawei, say.
Also as far as discussion here is concerned, most people here are from Western countries, so at the end of the day discussions will mostly be about our own behaviours.
It does no such thing. Being a hypocrite does not impact the correctness or incorrectness of what you're saying (which is why the tu quoque fallacy is a fallacy), doubly so when we're talking about entirely different categories of abuses that invalidate the hypocrisy charge anyways.
Listing off fallacies is great in internet discussions, but it's not how the world works. To be honest it's also not really how internet discussions work any more because everyone's grown sick of it.