What the hell are you talking about? Clinton beats Trump by more in the H2H matchups than in either the 3-way or the 4-way. Each of them is "taking" more votes from Clinton
Your presupposition seems to be that Johnson voters would otherwise vote for Trump, except that you have no data to back that up. The data shows that Johnson is taking away votes from Clinton - specifically among younger voters where Johnson is doing extremely well.
But it does sound like you know that Trump is going to lose and want to make a pre-excuse. So that's a good sign for those that want Trump to lose.