These weird semi-ideological ideas like "don't use margins!" "don't use mocks!" that keep popping up sometimes are leaving me unfazed nowadays. I used to consider them all strongly and weigh the pros and cons but now I feel like I have gained the experience to realize what this is really likely about. I think people come up with this stuff like they come up with political ideas at a bar. They don't actually believe this stuff strongly, it's just some random thing they thought up in the moment and then 5 years later they probably realize that they kept using margins all over their code but no, they didn't bother updating their blog post to do a mea culpa .. of course they didn't.