Sorry, man, I gotta disagree with you big time. Fair catching at the 10 happens all the time, and teams most definitely do have their returners call for fair catches in those situations.
Inside the 10, maybe not. Once the returner is down around the 5-10 yard line, the prudent thing is to let the ball go and hope that it rolls into the end zone. But if the returner is somewhere around the 10-15 yard line, you certainly do fair catch it.
The worst thing you can do is to catch it and try to run with it, at least that's the worst choice most of the time. The reason you don't do that is that when the punt returner is positioned at the 10 yard line, that usually means the punting team is punting from somewhere around midfield. That means the coverage team has less field to cover and can get to the returner much earlier. When that happens, the chance of getting levelled right after making the catch is high, and the chance of a fumble is also high.
On both of those punt returns, the receiver caught the punt with Cleveland players right nearby. That is a huge no-no. Those were very clear situations for fair catches, since Cleveland was also in great position to down the ball near the goal line if those punts are not caught.
By the way, I just watched the Green Bay punt returner call for a fair catch at exactly the 10 yard line.