Hope you know tether belongs to bitfinex exchange and not binance exchange so how can you ascribe this increase in the price of bitcoin to binance buying bitcoin to support tether, do you have any Link to back your new because that is the only way we can believe your news. And if I can ascribe the increase in the price of bitcoin to any thing It simple that is increase in the demands for bitcoin on the exchange.
It doesn't matter whose is Tether.
Every holder of this coin would be in trouble is something goes wrong, and there are crazy rumors about that right now. Every one is trying to secure their positions so it could be a point that individuals sell bitcoin for tether.