There is no appeal, really. He wasn't elected by the general public, he was elected by 0.35% of the population in the form of the Conservative party members.
He's seen as a populist, and a buffoon, yes, but he occasionally exhibits flashes of an intelligence rarely found in a politician.
Unfortunately though, he does appear to hold some rather elitist views, has more than once, made racist comments in public, and has been found to lie on numerous occasions, about a countless range of topics.
Even a number of his own supporters acknowledge these issues.
So it's very hard to believe his appointment will be a good thing for the UK.
So the sentiment is that May "didn't try hard enough"?
There are advantages to having a sociopathic buffoon in power willing to push through tough legislation, like Trump and immigration reform...provided they don't tear the society apart.
There's an equal chance his own party will help bring down the government, and force an election, to help prevent that catastrophic outcome (no-deal exit).
This is worth a read if you're trying to understand Boris Johnson: https://www.nybooks.com/articles/2019/08/15/boris-johnson-ha...