Hmm, well, I remember doing all those things as a toddler, and my younger brother doing them too when he was about that age.
Hot tea? Probably too heavy, and too hot for toddler hands to hold. As long as someone's ready to take it, then the toddler's just trying.
Champagne? Won't like it so toddler won't drink it.
Grandad's sweeties? Well, they're grandad's, so toddler knows they're off limits.
It's a different way of doing things, and one which isn't followed these days, so the surrounding understanding that I had as a child isn't there.
Yes, I know there were very good reasons not to do those things, and many children were hurt over centuries of doing it, and it's great that mostly that doesn't happen any more, that people's ideas of how to treat children has changed enormously. I know all that.
I'm simply pointing out that there may be reasons why they do those things, which may help you help them see why you don't do it and why they shouldn't.