Just a thought, but if you are doing your job right, and the people around you are not, you WILL be resented. You will not be well liked.
That those who have run as Conservatives and fallen far short of that mark don't like Cruz is no surprise, really. No one likes to be forced to confront their own failings.
This is different. Reagan was OPPOSED by many within his own party but he was not disliked. The same can be said for other conservatives. But Cruz is not only opposed, he is disliked.
Churchill was opposed but not disliked. Same for Lady Thatcher.