Well, there is one reason to fight and attempt to check questionable votes in situations such as these. Because quite simply, if the election ends in a large section of the country seeing it as having been stolen outright by blatant fraud with no attempt made to stop or prevent it, what do you think said section will start doing in follow up elections? You'll see more people on both sides starting to cheat in an attempt to match one another which causes even more cheating in response. At which point, well, do your elections still mean anything if everyone involved is cheating and is known to be doing so?