The mistake was made when Lyles took Hill seriously and started responding to his smack talk. Same with the YouTuber. He should laugh it off and focus on his own sport.
With Hill, he should have responded with something like "Tyreek is the man. Very fast on the football field and has shown that he can mix it up on the track as well. I would love for him to compete in some meets and see if he can make the USA team. We'd love to have him."
I learned this the hard way back in High School when a soccer player and I both got scholarships to the same University (I was a distance runner running 1600 and 3200). The soccer player was a friend, but I admit he was cooler than me, and he was known as the fastest kid in the State on the field. So naturally, people around school started wondering if he could run with me. Having an ego, I started talking smack back and the next thing I knew I'd agreed to an 800 meter race. I was a pure distance guy and didn't have a super fast 800. I was scared. The race was planned and even my coach was out there with a huge grin watching it go down. I won by 50 meters after easing up with 200 to go and everyone said he almost beat me and that he could run in college (he was a great athlete and likely could have been a solid middle-distance guy, to be honest). All I got out of the situation was a bunch of people telling me I was lucky he hadn't trained or chosen track.
The TL;DR moral of the story is to not get yourself into a lose-lose race, especially one that you might lose because it is outside your comfort zone.