I believe the key to understanding what Cruz did is to realize that he does whatever Mark Levin tells him to do. Levin is digging in and turning into a trumpbot and Cruz will not cross him.
I believe the key to understanding what Cruz said is in remembering he is a lawyer. Words do, indeed, mean something, and Cruz chose his carefully. He pledged his support and he was honoring that pledge.
He said Trump is the only thing standing in the way of Hillary, (qualifier), so vote for Trump if you want to stop her.
And that he would vote for Trump (to stop Hillary).
No where in there does he use the word "endorse".
Trumpkins have a history of filling in the blanks with what they want to hear, and they so wanted Ted to cave after months of vitriolic attacks, even beyond the primaries, that they read something into his statement he didn't say. The media said it, just like they said Cruz blamed street riots on Trump, or was the one really behind Liz Mair's pro-Rubio PAC, and a host of other delusions.
Now I supported Cruz in the Primaries (even though we didn't get to vote for POTUS in ND).
https://ballotpedia.org/RNC_delegate_guidelines_from_North_Dakota,_2016At this point, I am no longer a member of the GOP. I have no voice there.
While as a member of the Constitution Party, my voice may be muted, it is a voice.