After telling Jol he wanted to quit at the end of last season, he was left at home to train with the kids after being excluded from Fulham's pre-season camp in Switzerland.
Liverpool were then accused of making an illegal approach for Dempsey before Spurs made their swoop.
Jol admits the episode left a sour taste.
The Dutchman said: "He acted like a player who I couldn't involve any more. If you don't want to talk, if you don't want to run, if you don't want to do anything, if you want to train with kids I can't use you any more.
"But there was no approach and that was when the tapping-up situation arose.
"It's a long time ago now so we can talk about it. But you will get this situation in the future with more clubs and more players.
"I feel that is what he probably meant - you have to move on.
"When he went to Spurs instead of Liverpool, I thought that's not a bad move for him - good wages because they pay good wages now. There was maybe a bit of hard feeling but I can forgive him for that. He should just work and show what a good player he is."