Yes, his hard line will hurt him with voters. If Trump is not longer pivoting to a softer approach, then it will definitely and undoubtedly hurt him. He already comes on very strong when advertising and trying to get votes, so this approach will make it worse and worse and worse.
As Trump becomes tougher on controversial ideas he will further alienate himself from people. I do not think this would have been a problem for a more traditional Republican but Trump has many ideologies that offend and so there is almost always something that he says that someone will find offensive. This means that even his supporters may find that he now offends them and I think he's going to find that this damages him as he works to offend everyone.
Donald Trump's hard line stance on issues like immigration will likely hurt him with many voters. Trump had said he would pivot during the general election to broaden his base of support. Instead, Trump has defended his hard line stance on many issues, which will likely alienate him with many voters.
Of course, he has to pivot. He has to give the voters in the middle a hand to grab hold of and that is what he is doing. He could come out as a transgender African American now and it still wouldn't sway the base because they aren't voting for Trump because of what he says or does, they are voting against Hillary and that won`t change no matter how much he pivots.