Trump doesn’t say “bigly”, he says “big league”.
If people can't hear the "g" in big league, then they need to get their hearing fixed, not criticize Trump over it. They, of course, just want to portray Trump as someone too stupid not to know that "bigly" is not a word. Even MSNBC the other day had "bigly" up as a Trump quote at the bottom of the screen during one of his speeches (although they quickly took it down).