How can one claim Trump "hijacked" the party (a reference to a criminal act of one commandeering a vehicle that is not theirs) when he has received the most votes in a Republican primary from Republican primary voters? Can't the GOP just admit that a strong plurality of their voters actually like Trump and strongly believe in what he says? The old guard needs to stop pretending that Trump "stole" the nomination by "hijacking" the Republican Party. It is both silly and pathetic.
Because he's not a Republican. He has no history of active involvement with the party, and he's at odds with much of the party platform.
If a gunman takes control of an airplane and then announces "We're going to Disneyland, free drinks for everyone" the passengers may cheer (if they're idiots) but he's still a hijacker.