I definitely hear where you are coming from, many folks have covered the "me" complex that means others often show no respect and don't listen. To posit towards the other side though, the hypothetical person standing before you with, "Oh, do you ler sometimes too?" Isn't the same as the previous 10 people who asked that same question and to dump the frustration from dealing with those first ten on this person is a bit unfortunate. To Omaha's point, not every screen name on this forum specifically touches on the lee/ler side of things, some are completely unrelated (like mine). Even when they do say "ler this" or "lee that," it is not a safe assumption that just because Omaha would put the exact nature of their fetish in their SN, that everyone else does too. So if you haven't said otherwise, or placed loads of emphasis on "I just lee," then "do you ler also" is a fair question imo. If it helps, think of it as complimentary, that person is willing to put complete trust in you to tie them up and tickle them. Yea its a kink, but thats going to be my biggest lee block when I meet a 'ler because I can easily see some malicious person get a lee tied up, then steal their keys, card, car, phone etc and leave them tied up. You can bet every lee has worried about this so its really showing an enormous amount of trust in you, which goes in hand with a high opinion of you. Ler or not, I'm not about to let some arsehole tie me up to tickle me, especially not if they seem sketchy. So there's that.
Would also caution you from assuming that everyone you talk to is just a tickle hungry maniac, if they ask whether you also 'ler, they could just be making conversation with a potential online friend who shares their interests.
The second part of OP is pretty blatantly a self absorbed, tickle hungry, maniac. "What about your feet," is fine. Feet are a common tickle spot and I think there a sort of foot fetish adjacent interest that some tickle fets develop because its the kind of go to ticklish spot in the public eye, its often one of the most ticklish spots, and its furthest away from any ero zones so best candidate for the sort of innocent tickle that a person may lead in with before taking a relationship further. Where they went wrong is trying to force you, against your stated will I might add, to talk about your feet.
So all in all, unless you lead off with the statement of your preference and that its your only stated preference, follow up questions are polite, show interest in you, etc and if the follow up Qs are bugging you so much, just lead off with "I'm only a lee, and "my feet are off limits." That gives you the perfect 'douche-o-meter' since the sincere possibilities will respect that and when some dbag insists on foot talk, you can block them with clean conscience (so to speak)
) and knew she wanted to indulge both sides of the fetish. 
