Because he is not a conventional candidate and he does not write off any segment of the population. He wants those in Utah to remember he did ask for their votes and campaigned there when he is the Republican nominee this fall.
I can see Trump flying and having campaigned in every state by the time of the fall election. He has already campaigned in in every state except Deleware east of the MIssissippi. He has also been to Texas, Idaho, LA, ARK, MO, IOWA, NV west of the Mississippi. He will add Utah and Arizona this week.
We should keep a running tally!
But...but...but, he didn't get in line, pay his dues and wait his turn! < /GOPe >