Is it wrong to like tickling someone who doesn't like to be tickled? No, technically it's not wrong to like doing it. However, it IS wrong to continue to do it incessently when you know they dislike it.
Case in point, I refer you to my ex girlfriend from senior year of high school. Girl absolutely hated to be tickled, which caused a wee bit of an issue for me since, ya know, I tend to enjoy tickling and being tickled. As a result, I would lightly, quickly tickle her on occasion, but never anything serious because I knew it would end in me pissing her off, which would suck. She never knew about my fetish, so maybe if she did she would have lightened up a bit, but I opted to never pull the question up in our year long ordeal.
Slightly long story short: If it's gonna make the person mad, don't do it bulk. It's fine to like doing it, but there are simply too many factors to take into consideration, and if its going to do more harm than good, you should probably pass.
Least that's my two cents anyway.