Trump was on "Morning Joe," where he was asked to comment on that new Cruz ad, which includes a clip of Trump saying "How stupid are the people of Iowa?" Trump said that in the context of mocking Ben Carson's old story of a guy's belt stopping a stabbing attack. Trump was saying that Carson must think Iowans are stupid, because only stupid people would believe that. To present Trump's "How stupid are the people of Iowa?" as if Trump were saying Iowans are stupid is to lie about Trump.
Accordingly, Trump's response to the ad was: "He's a liar." With that, Trump continued:
"That's why nobody likes him, that’s why his Senate people won’t endorse him, that’s why he stands in the middle of the Senate floor and can’t make a deal with anybody. He looks like a jerk, he’s standing all by himself. And you know, there’s something to say about having a little bit of ability to get other people to do things. You can’t be a lone wolf and stand there. That’s sort of what we have right now as a president.""He looks like a jerk," seen in context, refers to Cruz's standing by himself and being a "lone wolf" person in the Senate. It's an attack on his governing style — not his face! — and Trump neatly connected it to President Obama's go-it-alone style.
The co-host, Mika Brzezinski, understood what he was talking about. She broke in to ask a question, and it wasn't about the inappropriateness of attacking a man's looks. It was about whether he really meant to compare Cruz to Obama. Trump first said "they’re the same," then took it back on the ground that "Ted is more strident" and "At least some people like Obama."