Yup the manyservers with 3 hours of practice and 2 minute races make no sense - for that we have leaderboards.
Practicing with a fuel and tyre wear with other people around is definitely not the same as hotlapping on a leaderboard.
The reason there is a 1, 2 or 3 min races is because you can't set a zero minute race in the dedicated server options, so if you want a practice server it has to run for a max of 6hrs but then has to go into a race scenario. Just sit the minute or 2 out in the pits and the practice will resume at the end.
In Single player, AI count as other people around, especially as you can configure their quantity, cars, level, they don´t drop in and out of the rooms and cause connection spikes. In multiplayer you also lose the session times when people leave so you don´t know if you set a good time or not. I don´t get why in a racing game with race in the name, so many rooms are not about racing in races. Must me be who crazy be..