Let me preface my comment with two things: I am not a Trump fan (or non-fan); one of the things Trump has excelled at - at a near genius level - for nearly a year, is playing the MSM's hatred into millions of $$ of "free advertising".
Speculating wildly, what are the chances that this was an intentional trap for partisans in the MSM and the Lib/Prog punditocracy and commentariat? To make them look silly and expose their partisanship? Further, what are the chances that the "plagiarism" in Melania's speech - 4 or 5 sentences in a far larger context - was intentional, to lure MSM-folk, et al, into this trap?
It's a total WAG (Wild-Ass-Guess), but I think Trump & team are easily that crafty.