I agree with Estragon. However, if you only win because of the other person's mistake, the win isn't as gratifying. Try to improve and be able to win because of your skill, not just others' mistakes.
Should I feel bad claiming wins due to blunders?

It's sad when a great game is cut short by a blunder, but all the same I would feel worse if I gave my opponent a do-over. The struggle between us as players is what makes the game interesting and when we give each other takebacks and free passes it cheapens the experience. That's my feeling.

"It's sad when a great game is cut short by a blunder, but all the same I would feel worse if I gave my opponent a do-over. "
Yeah. Sometimes I play my mom, and when she makes a blunder she askes if she can take it back. Sometimes I think it is ok to take back a move, like when you are playing just for fun, but never to get into the habit. Take-backs should be avoided and it would be better to just play with your opponent's mistake.
i use takebacks against the computer sometimes. lets me try a different line that may work better. i think it has helped learn a bit. and i don't think the computer is offended.

At our level sooner or later somebody is going to make the tactical or strategical error that will cost them the game, all wins against players of equal or greater strenght than yourself are "deserved" that is the nature of the game !

I also do a few takebacks, planeden, but only against the computer-it's not really a good habit to get into. I think the win is more gratifying when there are no takebacks.

I don't know of a chess game that has been won that had no blunders in it. It is indeed a part of chess.
I'm not sure that one should ever feel exultant in victory nor despondent in defeat. However, one must admit it feels better to win than to lose.
Here's one way to look at winning a game against a high ranked opponent when your win is a result of a blunder. First, as many have pointed out,every game has blunders. You are simply referring to a more extreme blunder than many others that might happen. i.e. a hanging piece, not typical of a player of that rank, as opposed to a weak pawn position that you might not even notice. In other words, every game won is, indeed, a result of a some sort of blunder. Don't knock yourself down because, in this case, he made the first one. Second, if you won the game because he made a blunder, it seems likely that you could also say that you won the game because you did not make a blunder. Rest assured that if you had made a blunder, he would have capitalized on it, and the "expected" result would have come about. This time, you played a perfect, or at least good enough, game of Chess to stay in it long enough for him to make the first major blunder. Finally, to carry the second point farther, keep in mind that it is easier to "blunder" against a high rated player than a low rated player. When I play someone more than about 600 points above my own rating, I find myself constantly thinking about moves, and then realizing that I would lose a bishop on that move, and I would lose a rook on that move, or a queen on that one, or have lousy king safety on that one, or checkmate on that one, or whatever. In other words, not only did you stay alive long enough for him to make a blunder, you did it in such a way that he couldn't force you to blunder first.
So, pat yourself on the back, but don't brag about it. And, if he offers to play the next game for money, it's not a good idea.

It depends on how big the blunder, i once played some one who saw a chance for a quick mate using his Queen and Knight, unfortunately he/she did,nt see the threat to his Queen from my Knight, i did, and took his Queen, i won but it was a bit hollow.

You should not feel bad about claiming wins due to blunders. The win may be a little hollow, but don't feel bad.
In a casual game once in a while my friend will hang his queen. When he does then the game becomes a cake walk. Sometimes I let him take back the blunder and make a different move. Where's the challenge in beating someone that has dropped their queen? OTOH if this happens in a rated or tournament game I will take full advantage of the mistake with maybe a slight twinge of guilt.