I think it's bad because it comes across as someone discovering basic numeracy as an adult and going "what happens if we treat happiness as a countable object and do basic adding up on it?", and then never gets past either of two major stumbling blocks: (1) how do you compare the happiness of two different people, and (2) there's a lot more to maths than adding things up, important maths at that, such as "when is it OK to treat discrete things as continuums and when is this a bad idea?" and "do you really want to say that m people who are n happy is the same value as one person who is m*n happy, or is there some kind of discounting for bigger values like there seems to be with the utility of money going down as people get richer?"
> *Everybody* understands that when the founder of a Thing does something as daffy as Having Themselves Mummified in Victorian England the rest of their thinking is automatically suspect.
The main thing with Rationalists is that they recognise everyone's thinking is suspect.
> It's the kind of informal heuristic which is almost never wrong. We should not ignore it.
I grew up in the UK, with a prime minister who promoted what she thought were "Victorian Values". Amongst other various things, when she went to see Peter Shaffer's play Amadeus, she was informed of Mozart's scatological humour and is reported to have responded thusly:
"""She was not pleased. In her best headmistress style, she gave me a severe wigging for putting on a play that depicted Mozart as a scatological imp with a love of four-letter words. It was inconceivable, she said, that a man who wrote such exquisite and elegant music could be so foul-mouthed. I said that Mozart's letters proved he was just that: he had an extraordinarily infantile sense of humour ... "I don't think you heard what I said", replied the Prime Minister. "He couldn't have been like that". I offered (and sent) a copy of Mozart's letters to Number Ten the next day; I was even thanked by the appropriate Private Secretary. But it was useless: the Prime Minister said I was wrong, so wrong I was.""" - https://en.wikipedia.org/wiki/Mozart_and_scatology
Lord Byron is also famous both for his poetry and for bringing a pet bear to his university accommodation to spite the rules about no dogs.
There's weird anecdotes about virtually every famous figure, 'cause humans are weird.