So you are arguing let's set up a "standard" that's wrong on both sides? I'm not trolling by the way just going by how you defined the word. What would be the point of that?
Both sides can act wrongly, absolutely. It's about what behavior you tolerate without noise and what you loudly denounce.
If we're debating, and you say "I don't tolerate lying", you're credible. If you only focus on Trump's lies and call any reference to Biden's lying as a "whataboutism", you're simply defending Biden, and just a political activist.
I think I might see your logic. It's not a logic I agree with, because in effect it would be a blanket excuse for every politician to act however he wishes since there is absolutely no objective standard in your logic to determine similarities and differences between 2 events. It doesn't allow for context.
Let's say in your lying example. If we debate and I tell you one lie. And you debate and tell 1000 lies, by your logic, we are both liars and I lose the right to call out that you lied a 1000 times more than me.
No, of course amount of lies matter. If proven lies are given by one than the other, then that needs to be addressed.
However, that's not the case. In the modern context, with the new definition of the word "lie" once Trump was elected, other factors get introduced, such as the clear bias of "fact checkers" who don't check facts but merely given their own judgments on the situation and call it "Fact". Despite the media pseudoclaims, Trump wasn't some increase in statistical, proven lies. And I'll denounce any lie he told, but I can also list so many massive, horrendous Obama, Clinton, and Biden lies as well. When held to the same "fact checking" standard, they're not far apart. That's why the left had to change the definition of the term to include perspective, context, and narrative, which I reject.
Wrong facts aren't what we think he meant, or that he didn't consider factors we think he should've. That's what the left uses to simply build up a high number of "lies" on Trump.. so they can sling the high number around to the laypeople for shock value. People can give their perspective and judgement all they want, but they can't call it a "fact", and they can't call things "lies" because they simply disagree with it.