the problem is, even in the official rules, it doesnt specify the timing which is why i maintain it should be after the player lets go of the card; technically the player hasnt played the card until theyve at least put it on the table, but my opponent was trying to call uno even as i was putting it down and i still said uno before them, it's just annoying if someone is going to try to call uno the split second you start making your move.
my reasoning for the hands off the card rule, is that that's the point when you've officially played the card. furthermore i think the Uno rule is designed to punish people who forget to say "uno" rather than as a means for people to wait on your play so they can say "uno" the split second you put the card down. there should be a somewhat noticeable beat in time before someone says "uno," in other words, the player needs a chance to say it themselves when playing the card