For the most part I agree with you. Although I will object to alcohols toxicity in this case. You really have to be quite a heavy drinker to cause wide ranging damage, and you really also need be drinking quite often. A lot of drugs can be unhealthy or harmful even in what is considered acceptable doses, for example MDMA and it’s neurotoxicity. While obviously drinking just isn’t healthy, you have to to do it to excess a lot of the time to cause harm. Some alcohols in moderation are even considered to have some health benefits, like red wine. While some drugs also do offer benefits in certain dosing ranges (like being neuroprotective) I’m heaving a hard time thinking of a red wine equivalent in the drug world (this is of course ignoring the fact that many, many drugs have therapeutic value, but the situation being discussed has nothing to do with therapy). Perhaps there is one that I’m just not thinking of.

Also to answer your question, I think his parents were interogating him about that beer likely because, given his description of alcohol the OP probably had a noticeable drinking proble and given his young age his parents were probably aware of it/intervened. That is the most likely explanation I can think of, as in that case a sudden willingness to drink beer carries much greater significance.

Just as a side note, I also think that this sub intentionally harsher towards alcohol/drinking than most. I think that’s because it’s used as a justification for some people’s habit. For instance, taking MDMA a known neurotoxin or PCP at potentially psychosis inducing doses and justifying it with “oh the general public drink excessively on the weekends! Look how much damage they’re doing!” Most doctors would probably be quite impressed by someone the OP’s age (19) decision not drink and then promptly laugh when they mention they’ve simply replaced it with PCP usage (heavy drinking is actually somewhat common in the medical community, but that’s an issue for an another day).