It's very easy to find examples where both Bushes, Clinton and Obama allegedly violated the War Powers Act.
If you think presidents are following the law then you aren't paying attention.
Key word here is
allegedly. They are testing the waters in a way, but doing so carefully. If
you think the President gets to do whatever they want, then
you aren't paying attention.
If the President were to brazenly violate the act, and
Congress were to call him out on it, it would initiate an immediate constitutaional crisis, which could only be resolved by the courts. If the President wins, that fine; they get their way both now and in the future. But if the President lost that fight, the result wouldn't be "curtailment of executive power", it would be "The President has violated the law and the Consitution." No "if"s, "and"s, or "but"s. Forget not getting re-elected, that's impeachment material right there. And since the Supreme Court has signaled they aren't interested in debating it, the only scenario where they would is if they were forced to by a crisis. So the President can't challenge the law without playing a game which can easily lose them their office. Of course, as long as no one calls the President on what they do, it's fine; so the President has to be very careful to make sure they don't call him on it (which he does by making a show of adhering to the law), because if they do, he'll be forced to back down or go all-in on a very uncertain outcome. So the President doesn't want to follow the law to the letter, but they
cannot afford to be challenged on it, because either they back down (and have to back down on claiming it is unconstitutional) or they don't, and risk everything.
So don't be so rude. Things aren't so obvious as they appear.