In response to the op, first, the US government moved over 15k bitcoin worth about a billion dollars, where did they move it to?, to coinbase, what is coinbase? An exchange, infact, the biggest crypto currency exchange in the US at the moment.
With the above information, we should already be certain or sure that they moved those bitcoin there to sell it, and should we be worried about this?, to me, I would say "absolutely not", because whether now or later, they are probably still going to sell the bitcoin, so, the sooner they sell it off, the better, at least, we know one whale have left the market.
But I think it's wrong to refer to the US government selling the bitcoin they seized as them taking profit, how does one take profit on something they did not buy or invest their hard earned money in? They simply are selling, I do not consider t this as taking profit because they did not buy those coins.