His son had to physically restrain him from drafting Johnny Manziel. He hasn't changed as much as some people think.
If Russell Wilson (who is on the downside of his career) can be traded for multiple picks, then Justin Jefferson (who is in his prime as a generational talent) can be as well. Either the Vikings pay him QB money or they trade him to someone looking for that final piece to win a title. Letting him walk and getting nothing in return is not an option.