I've always been very supportive of Madonna during the course of her career and would often defend her when unduly attacked. Madonna took digs at Pope John Paul II, George W. Bush, Sarah Palin and Marine Le Pen (among others), so it's nothing new.
On Pope John Paul II: "Absolutely. Catholicism is what I was raised with, that’s the religion I know, but I disagree with almost every principle of it. If I ever got into a room with the Pope, I would probably fly into a rage with him. All of this adulation. I don’t think people realize what he’s actually saying. I mean, women have literally, absolutely no rights in the Church. There is no freedom, there’s no choice. I know a lot of Catholics who go to church, who practice, but they don’t agree with three fourths of it. But it’s good to have faith, and I love going to church. I don’t necessarily like going to mass, but I do love going to church." http://allaboutmadonna.com/madonna-library/madonna-interview-spin-january-1996
On George W. Bush, US President at the time: "Go to Texas, where you can suck George Bush's d*ck!"
On Sarah Palin: "Sarah F**king Palin!"
As for Marine Le Pen, she got a Nazi cross on her forehead (during the 'Nobody Knows Me' MDNA Tour interlude).
But this time, it feels different. The White House (akin to Buckingham Palace) is sacred to Americans. Not everything needs to be said in public. What Madonna said kinda cheapens and defiles the sanctity of the White House. In other words, "If I don't agree w/ the current régime, the whole White House (home to the President) might as well be blown up!"
I understand she may not have seriously considered blowing it up, and she then explained despair (violence) is not the answer, but that particular White House reference was not so wise nor advisable. Besides, there are many crazies out there contemplating ways to actually assassinate the President (regardless of how that would affect his 10 year-old son, Barron).
Back then, in 2003, being against Bush and the US military action in Iraq was somewhat more risky (Madonna ending up pulling the 'American Life' MV from the airwaves and the net), but now, the anti-Trump sentiment is so strong that in spite of criticism, Madonna's receiving tons of accolades.
Being publicly pro-Trump (like singer Azealia Banks or former actress Kimberlin Brown) takes a LOT more guts. Aaron Carter experienced heavy cyber-bullying after his public support of Trump (support he ended up withdrawing). Carter also confessed to having been emotionally distraught by all that bullying (which shows a lack of tolerance from anti-Trumpers).
In my observation, the anti-Trump sentiment is completely irrational. Reinforcing homeland security, stopping illegal immigration, eradicating radical Islamic terrorism and drastically improving the economy are some of Trump's top priorities. One may or may not agree w/ the way he's going about things, but that mounting tension ain't solving anything. And not all Trump supporters are racists, religious nutjobs (like pastors calling for gays to be killed) and what not! What about the Left just gives him a chance?