Quite frankly, Specter hasn't been loved by Republicans for some time. The ONLy real "conservative" bedrock stance I've found him to be strong on was the 2nd amendment. In every other issue he is either about as moderate as you can come (having a mix of positions or just no strong real feeling), liberal, or conservative in the meekest least outspoken way possible.
Specter rarely made the news because he was strongly pushing for a fiscal budget, or to push for tax cuts, or for calls of needing to shrink the size of government, or to strengthen our borders, or to other things. He was generally only in the news when he was pushing strongly for the "amnesty" bill, was blocking conservative judicial nominations, or was one of 4 to 7 republicans that would jump over and side with Democrats to break fillibusters or sway a big item.
I think if Specter had been at the forefront of a conservative issue or two he'd have had a lot less vitriol shown to him; likely more on par with McCain, who gets insulted but also praised, than with someone like Olympia Snow who I've never seen a good thing said about. But he wasn't, he was a meek quite person on almost all conservative issues unless he was jumping ship to the other side in which case suddenly he was loud and prone to lectures.
His cache had just gone down in recent years becuase there was less of a need for a token republican to drag over to make something "bipartisan" in hopes of getting it to pass or put onto the floor.
"I am appalled that somebody who is the nominee...would take that kind of position"
"A court took away a presidency"
"...the brother of a man running for president was the governor of the state..."
It's horrifying because Trump is blunt instead of making overt implications.
"He who does not think himself worth saving from poverty and ignorance by his own efforts, will hardly be thought worth the efforts of anybody else." -- Frederick Douglass, Self-Made Men (1872)