Does the phrase below have a critical tone?
几个运动员应该尽到自己的努力了， I suppose / guess some （几个） of our participants must have tried their best,
Yes, it does have a critical tone
几个运动员 means "a few athletes"
应该 here means "likely"
尽到自己的努力了 = " had tried their best"
What he actually wanted to say was "most of them had not tried their best"
(He didn't want to say most of them were bad directly, so he turned it around and said a few of them were good. It is like saying someone have a good heart to avoid answering is he ugly or not--of course he is ugly!)
The following sentence:
But there are particular individuals having problems in particular events.
He had made an understatement. Again, to avoid calling out most of them directly-- He didn't make it clear that these 'particular individuals' happens to be 'most of them'