You forget that most often such a lane is as wide as a bicycle + 10 cm on each side. Meaning that if a car passes fast enough it could even push the cyclist around just with its air flow. Plus, at lower speeds bikes tend to go less than straight, so there is a fairly real danger of bumping into, e.g. the mirror on a car. Additionally a cyclist is obligated to handle things coming at him from between parked cars and such, which is really tricky since a cyclist is often much closer to those than a driving car. Those and more i don't have in mind right now are plenty important reasons why taking a lane can make traffic safer for everyone.

Having been in the situation often enough, i can also tell you: I wouldn't mind if cars passed by me in narrow situations if they slowed down while doing so, but more often than not, cars pass by at full speed instead.

Lastly, keep in mind that this situation only happens in narrow side streets, not on big streets with better separated traffic flows.

Sport cyclists taking a whole lane while ignoring a dedicated bike path are just assholes.