It's not wrong. You can feel it.

My wife is not a gamer and even she can feel it. She hated playing on our living room TV. Said she felt like she got really bad at Mario Bros over the years or something and was disappointed.

Bought a CRT; she loves the game again and is still quite good at it actually.

Reacting to stimulus is completely different than timing inputs in a video game. A few ms of delay isn't really going to register in a reaction test, but if you're using constant time sensitive information on screen to accurately time your movements in a game, you can easily feel lag in the sub 5ms range.

As a guitarist, I can feel latency down to 2ms if I'm playing through a modeling amp on my PC, especially if I'm playing at high tempos. The faster you play, the greater the percentage of time between notes that latency becomes. The effect is the same in high speed video games.