That is what follows logically from your premise. If every time Trump is called out for doing something bad, the only reaction you can muster is well, all politicians are bad you are then justifying the behavior, allowing it to continue, and failing to recognize that no, all politicians are not as bad as Trump. You are implicitly saying it doesnt matter because they are all the same.  If they are all the same, then what I said is true; nothing matters. If it wasnt Trump lying to us now, itd be someone else lying to us and the result wouldnt be different. Unless you believe otherwise? Which is it; are all politicians equally bad? Or is perhaps Trump demonstrably worse and is in fact different and unique in many ways? If you cant bring yourself to criticize Trumps lies, crimes, and bad acts without also grouping in all other politicians as being equally guilty at the same time, how can you make the case that presidents and other politicians are in fact different from each other and can lead to differing outcomes, some better than others?