I voted for Cruz (who won) in the Texas Primary. All else being equal, I think he would have been every bit as teflon as Trump has been, able to take the s**t given him by the Left and throwing it back to them 10 fold. Politics is nasty, even within Party primaries. Get used to it.
Once it became obvious that Trump was going to be the nominee, I was all in for Trump. At that point, Cruz went into never-Trump mode. He was allegedly upset that Trump insulted his wife. But this was after some Cruz PAC (not necessarily connected directly to Cruz) made remarks about Melania being little more than a nudie model. Cruz also foolishly named Carly FioRINO as his potential running mate.
Once the RNC nominated Trump, Cruz should have been the good soldier and endorsed Trump. It's what one is supposed to do at a convention. I was screaming at the TV as Cruz made his "vote your conscience" speech. If voting one's conscience meant anybody other than Trump, then he was suggesting voting for Hillary. I remember Tucker looking stunned after Cruz's speech, and he said something like "I've never seen anybody destroy their own political career like that". Fortunately, Cruz came around and supported Trump for the 2016 election. But his antics certainly did not help him in the race against Beto.
But getting back on point, Cruz was not being trashed on FR for daring to run against Trump. He was trashed for putting his ego (or hurt feelings) ahead of country and party when he made that ill-advised RNC speech. At a time where the party needed to present a united front, Cruz was sowing discord. Unfortunately, some FReepers still have not gotten over it. I supported Cruz in his last election and do think he is one of our best senators. But that night at the RNC was a huge mistake for him.