Yes, I guess he meant he couldn't do high intensity in training. But that's serious enough if you fatigue overly fast in stages and it's already an issue at the Dauphiné as well. You've got to take stuff like this more seriously, it's not that a body is a machine where you could exchange parts or repair it.
Steels also said after he left the race, that he advised him to get out so not as to jeopardize the entire season. I'd say that's a very very very late point in the race to come up with this idea, knowing full well in his case that Remco's body isn't doing what it needs to do, or would be supposed to do if healthy.
Of course as
@Cookster15 said he can't know his true level before he goes, but given the run up, including winter and the crash, starting the season late and with full knowledge that your body isn't reacting properly, I find it wild to go to the Tour and say: well let's go for GC!
It's a huge goal so I understand that they at least want to try, but looking at the result, except for the TT, was it worth it? I guess his recovery will tell us if it was.