I appreciate that you are taking me up on the semantics, this is really important to the discussion. The key part of the definition is the “applied” part.
In server browser-based games like Team Fortress 2, highly skilled players will often split themselves between teams voluntarily, so that the match is not one-sided. In that case the players apply their own handicap, and it is each player’s prerogative to do so. In the case of Overwatch’s Competitive Play, the handicap is applied automatically by the Matchmaker, as it refers to each players Match Making Rating and arranges teams accordingly.
Team Fortress 2 players know each other from playing together on the same servers, and from a scoreboard which features full stats on each player. The handicapping of the match necessarily and completely depends on players’ knowledge of their skill relative to their peers. Overwatch players are always complete strangers to each other and never know any of their teammates’ and opponents’ performance stats (kills/deaths/assists), because the system is making the decision for them and segregating skilled/unskilled players based on the hidden performance stats.
But the biggest difference between Team Fortress 2 and Overwatch though, is that Team Fortress 2 does not purport to rank players based on their skill. Players would not voluntarily accept a disadvantage if they were being judged on their record of win/loss and performance.
If matchmaking in Overwatch was SR-based and truly random, it would not constitute handicapping and would be analogous to the wind on a golf course. However, Overwatch’s matchmaking is not SR-based, it is MMR-based and not random at all.