Is refusing to draw a game unsportmanlike?

When you come to a position that is clearly drawn, and neither side has any clear way to make progress barring an absolute blunder by your opponent. Opposite bishops being a good example.

If from a position as I mentioned above you shuffle and shuffle and shuffle your pieces around just waiting for a blunder beyond 50 moves b/c you save a fruitless pawn move or 2, and your opponent don't budge at all... and you make what should be like a 40-50 move draw by agreement... declining 10+ draw offers through out the game... turning it into a 180+ move draw b/c of the 50 move rule...

Are you just being unsportsmanlike or what? Is there another word for it? Is this an ok strategy? b/c The impossible hard computer has done this to me on numerous draws and it is sooooooooooo annoying

there is plenty examples where opposite bishops isn't a draw

http://www.chess.com/article/view/opposite-colored-bishops2

from article

"At this stage opposite-colored bishops are often a sign of a draw. Sometimes even being a few pawns up may not be enough for a win since the weaker side may build a fortress. However, my experience from watching online broadcasts from tournaments (or commentating myself) shows that people often overestimate this concept and are eager to announce “a dead draw” in ANY opposite-color bishop position, which is not the case."

http://www.chess.com/livechess/game.html?id=268062231

an example of this in one of my games... for the last 100+ moves I'm the guy moving the king back and forth 1 square offering a draw every few moves until finally i get it

http://www.chess.com/livechess/game.html?id=238776098

a 2nd example where I offered a ton of draws in a drawn position and it got dragged into over time for no reason lol

@ GM Cainite: I've seen a lot of games where people agree to a draw because they think it is dead draw afterwards the computer finds a win for one of them.
my point is that some evaluate a position as drawn because they don't want to fight or do not know how to proceed. I would say I wouldn't always know how to evaluate a position as dead drawn always. I think it isn't impolite to decline a draw if you have doubt. Opposite bishop isn't always draw and so on. even grandmasters agreed to a draw in won positions due to Quiescence error.

Well, games of 100 or 200 moves are excessive. But, could a reason be you were playing a computer in these games, so it did not notice it was a draw?