toryandproud: why do people feel the need to say "I hate the guy / the Tories, but..."
Because a lot of recent politics has been deliberately divisive and encouraged people to treat those they disagree with as The Enemy. So it's important to many people to demonstrate that they treat humans as humans despite fundamental political differences, and don't reserve their good wishes for "their team."
And in my case, I'd add that my good wishes for Johnson are for him as a human being. I wouldn't want any one to confuse that with support for his behaviour or actions (as some media are wont to do).