Europe is a mess. If they are American bashing then our best move is to give it all the credibility you'd give your little brother as he struggled thru puberty.
I want to start by acknowledging or accepting the chart at the beginning of your post as fact (or close enough for me to not need to verify).
I'd like to see the NATO countries get to the 2% of GDP level and I don't mind seeing them get slapped around a bit to get them focused on it. I don't like Trump's methods much but won't complain if he gets results. (I consider myself apolitical but probably appear pretty Libertarian mostly.)
I've got two big reasons for not caring much about how much we spend on NATO in absolute or relative terms. We can afford it and here is what we get for it:
I'd rather see us fight the Russians in Europe than have to try to take it back after they fold. Defense in depth beats holding them off at the wall, every fucking time.
Our fighting forces are mostly young people and I think they get huge lifelong benefits from being stationed anywhere overseas. I think I did.
Should we be trying to get a better deal in NATO? Of course! But a strong NATO is such an obvious advantage for us, for US, that it is no surprise we're paying for it.
Regards,
Rick