If you want to argue that comments should not be made about appearance you ought to demonstrate that yourself.
The Rayner story should never have been written or published but I think it ties with William Hague's Comment in the Times today. "Boris will have to change if he's to survive" which comments on the PM's "inconsistent behaviour and erratic messaging" - specifically but not limited to apologising to the house but immediately undermining that apology behind the scenes in the 1922 committee. He has a split persona - faux contrition followed by a "festival of bombast". "Im very sorry. I've done nothing wrong."
"If they give a different impression of their values and priorities behind the scenes to their public posture, it will always cause trouble. Aides who resign reveal the difference — as has happened with Dominic Cummings alleging that Boris said “let the bodies pile high”. MPs become troubled and less likely to be sure of their arguments. Officials don’t know which persona of their boss they are trying to serve."
I suspect the Tory MP that gave that quote about Rayner did so because they thought - or were lead to believe - it would be approved of. They don't know who they are cheerleading for or what he represents because of his mixed messages.
He is the moral vacuum at the heart of government and that does matter because his deliberate blurring of red lines and accepted behaviours (like abiding by the Ministerial Code) gives tacit permission to the sycophants (Dorries/Fabricant) the bullies (Patel) and the corrupted (Paterson/Hancock) to carry on. Under Johnson's leadership there are no standards.
And Johnson wins both ways - pathetic story draws in right wing misogynists AND he gets to pretend he's furious (just as he was furious about the stories of parties at Number 10). So he gets away with it because he presents himself as all things to all people - which is impossible if you have any core values.