In freerolls sometimes play silly, but it happens only in the beginning. Closer to the final table there are strong players, but they are also mistaken, because it is natural for a person to get tired and make mistakes. I play freerolls, because it's free money for the game. Moreover, even in tournaments for money, many players go Allin from the beginning having A 2 or something worse. Professionals in live tournaments also sometimes very aggressively play trash hands, and allin go without having anything. Another thing is that they do not do it pre-flop, because there is no benefit from this. Is that the hope that everyone will fold and will be able to pick up the blinds, but the benefits of this are really small.
But poker is so interesting that different tactics of the game are available. Players running allin deserve my respect, like any other players at the table. It is clear that they are unpleasant for those who prefer a different strategy. But they exist and with this it remains to measure up and somehow learn to play against them.