That is partially true and partially a right wing talking point. NATO had underfunded spending during the period they thought Russia was moving towards a more peaceful mien. Once Russian intentions become apparent they began moving towards the two percent of budget goal. The misleading part of the statement is that NATO moved towards significantly more investment as a result of the summit (and the antics of our glorious leader.) In fact they simply reiterated that they would continue moving towards the 2% goal.
www.factcheck.org/2018/07/trumps-false-claims-at-nato/
One must also understand that NATO is an alliance meant to stop Russian expansion. For the president to insult our NATO allies, question the purpose of the alliance, and then show himself to be Putin's puppet does the exact opposite of making NATO stronger.
Obama, press conference, October 18, 2016 : "But the larger point that I want to emphasize here is that there is no serious person out there who would suggest somehow that you could even rig America’s elections, in part because they’re so decentralized and the numbers of votes involved. There’s no evidence that that has happened in the past, or that there are instances in which that will happen this time. And so I’d advise Mr. Trump to stop whining and go try to make his case to get votes."