https://en.wikipedia.org/wiki/Denatonium is used to make it unpalatable. Fun fact: the same chemical is also coated onto Nintendo Switch cartridges to discourage children from putting them in their mouths.
Nowadays we just measure pressure differentials.
Methanol sales were banned in Finland prior to EU and Finland applied for the exemption already in the EU application in the early 1990s. It was finally granted in 2019. Probably around 500 people died and many got blinded meanwhile.
If you close your nose the taste is just bitter, but bearable. The additives are supposed to make you vomit, but for me I only had vomit reflex for ~5 seconds after swallowing. I could live with that if I was addicted and couldn't afford a regular alcohol. I'm sure many people do.
Not sure what the moral is. I guess that addiction is a really strong motivator, and tax evasion is not a good enough reason to justify killing people with poison.
I suppose wormwood is an acquired taste, but it's one I happen to like. They still put it in many different bitters here in Sweden.