I dance Morris, English country, "Playford", ceilidh/eceilidh/barndance, danced Scottish briefly, had a go at French dances, done some contras and so on. (How do you think I was able to put that list together!)
The point that people miss is that the only reason the grumpy buggers get the mentions is that they are so very much in the minority.
In any field you will find someone who takes their "art" and themselves way too seriously. Similarly, you will find leg-pulling and banter like my previous post.
While I have met one or two of the scowlers, I have to say that at every event, every dance, every event that I've been to I've been made welcome and helped when I needed it.
That includes about eight different folk clubs in Bristol/Cheltenham/Gloucester and Dorset.
At the same time, is only fair to point out that if you're a ceilidh dancer you will be very limited at a country dance session because there are simply more moves in country dancing than the average ceilidh dancer ever meets.
In other words, he's right. You CAN'T dance their dances.
If the event to which you refer was a dance, then the person at the other end was doing you a favour. At a dance they will call the moves, there will be a walk-through just like a ceilidh, but the moves will be more complex and there is an expectation that the dancers will have a clue. If they had to teach the moves in detail, they'd never get any dancing done and they'd get bored - and you would have been floundering all night.
If, however, you go along to a few club nights, they would be very happy to teach you - as you point out, we all have to start somewhere - and now you know where.
Ceilidhs, in contrast, have to start from scratch each time (usually) so the moves are a lot simpler. You still get the scowlers, but you have obviously managed to enjoy yourself despite them. You should be able to do the same for other dance styles and maybe broaden your horizons a little.