If you have a question or dispute over a warning, you need to U2U a mod for help.
I know nothing of why you were officially warned, but I'll give you my personal interpretation:
It wasn't for saying "holy cow", it was because you put up a "Hey yall! Watch this!" post, and it isn't considered funny. There are T & C
guidelines that the mods can fill you in on better than I can.
Posting to express an opinion in the correct forum is good, posting to educate is good, posting to question something outside ATS is good, but if it
concerns ATS, I have seen that it is best handled by U2U'ing a MOD for assistance.
Sorry you are having a bad day, I hope it gets better.
Live and learn,