AOG - there seems to be something of a royal 'We' in your OP.
I do condemn him for saying that some Mexicans are rapists and murderers - so are some French, and Japanese, and British, and Americans - so to single out Mexicans in order to inflame his supporters is derisory behaviour.
I have not arranged any petitions, or signed any either.
But to get to the point of your argument -
Donald Trump is a politician. You are willing to cut him some slack because he has never been a politician before, but really, if you are going to seek the election to the Presidency, it behoves you in some measure to start boning up a little about what your new job involves - that would be politics in the main.
I have no problem that Donald Trump doesn't know what being President is all about - but I have major problems with his wilful intransigence in either taking advice, obeying the laws of his country, or generally acting as though he understands that he is not in Trump Tower anymore, and he can't simply do what he wants when he wants, without opposition.
As to the attacks on his appearance - well, he is a politician now, and politicians have been subject to personal ridicule as long as there has been media to ridicule them - it goes with the territory.
But President Trump is so ludicrously thin-skinned that he has yet to understand that part of the dignity of office is to ignore ninety-nine per cent of attacks, not have hissy fits and insult people the way he does.
Meryl Streep makes a veiled accusation about him in a speech, and he comes back calling her a 'so-called actress'. She is the most awarded actress on the planet, does he have any idea how petty and small-minded his retort sounded? By all means answer her point, but to personally attack her universally recognised profession abilities is pointless and stupid.
A judge over-rules his self-made decision about immigration, and is called a 'so-called judge'. No President Trump, he is still a judge, elected and serving, his status is not reduced because he went against you, but your status is reduced because you took it personally and hit back with another childish insult.
It is these behaviours that mean that the standard robust debunking of political figures, which happens in every democracy in the world, is only going to ramp up, because he asks for it every single day.
The fact that the President of the United States uses fake tan and makeup and a hairstyle that a pantomime dame would balk at shows his lack of personal dignity and self-awareness, and that makes him more of a target for lampooning, not less.
The UK media don't lampoon him just because he is a buffoon, which he is, but because he calls them liars to their faces.
Another in a massive series of indications that President Trump is not only not fit for office, he is showing no signs of becoming fit for office anytime soon.