The primary target audience for hacker-to-hacker Postgres evangelism is MySQL users. Because let's face it, the choice for DBs like Oracle is usually made upstairs, and for very different reasons.
So why do Postgres advocates insist on dissing MySQL with false and misleading arguments? The usual target is some default settings, when obviously there are three kinds of MySQL users: the ones that actually have a reason to want less strictness, the ones that know how and when to change the settings, and the ones that just don't give a fuck.
You're not going to convince the latter until you are #1, and you're insulting the intelligence of the first two, whilst also making them question whether the arguments in favor of Postgres are actually true, since you're not being particularly honest in your criticism of MySQL.
And you're wondering why Postgres doesn't get any more love?
Most MySQL users are well aware that Postgres is technically a better DB. They mostly (right or wrong) feel MySQL serves their needs sufficiently, and are not particularly attracted to an open source community with such a douchy attitude.
If even Oracle doesn't scare people of sufficiently to jump ship and switch to a better, free and open database, you've got a serious image problem. Stop blaming it on other people's "stupidity".