I wouldn't even call Lefevere's comments stupid, more like brutal. He knows exactly what he is doing. Stupidity requires the lack of self-awareness.
When Oleg Tinkov made wild comments there was still something unserious and cartoonish about them.
Also stupid in my opinion, because it doesn't look good for sponsors in my eyes, at least some could be kept away. And in the long run riders might eventually ask themselves whether they want to sign there - as long as the team is very successful nobody will care, but if there is a dry spell for some time people might wonder whether this is the team to go to.
He puts his ego above a tactical at least semi-diplomacy, probably because he feels the Bora-return as a personal defeat, and I don't know how well things are going at the moment for him at DQS, other teams seem to be more successful at the moment in signing promising guys?
Also he boasts about how he doesn't need mental help, while others do (although he thinks it's a good thing for others, he of course doesn't need it), that sounds very childish.
I'm all for open talk, but this is pure ego making disrespectful and tasteless remarks.
I'm not saying these things always come back to you - they don't always do. But sometimes they do.