Ok.
As a fighting game buff, I have a pretty good idea of what cheap is, having seen it too many times for my own liking.
Cheap: A technique that, when used, restricts the opponents freedom for full play and manueverablity, putting them at a disadvantage unless they can counter it, despite being completely between the rules. Generally are difficult to counter as well, or at least take some time to figure out. Once one figures out how to counter it, it does not become effective anymore.
An Example: The Ryu Technique: Shooting Hadokens repeatedly until the opponent comes close, in which case.
Another Example: The Dizzy Technique: Continually using a 1-Hit KO move to win matches against the unprepared, instead of actually defeating them (Note: is only cheap if this is used over and over again an extreme amount of times)
Wavedashing is technically not cheap because it isn't part of the game, it's a glich, as such, it is technically a cheat or, at best, an exploit.
Casual players dislike cheapness, myself included, because they play for fun, and a restricting environment generally impedes that, as well as producing an feeling of being cheated.
Tournement Players turn a blind eye to cheapness because they play to win, and thus have no qualms about using.
After a while, both types of players can become indifferent to cheapness, as, while restricting and somewhat unfair, they are also usually simple and generally amateur-ish, and, once a counter is discovered, become somewhat useless unless part of a bigger strategy.
However, I often hear people call others cheap for reasons that aren't cheap at all. Mostly you hear people who are both arrogant and immature at the same time (the kind of person who takes to insulting those who beat him/her), and, instead of losing with grace, proclaims that their opponent was cheap. Thus, calling out cheap has been seen as the call of a whiner, which it really isn't.
So, as such, cheapness while cheapness can be countered it still takes away from the freedom of the game, although it can still be fun finding a strategy of your own to overcome the assailing strategy.