A moderator here wrote an article about how to downgrade to previous versions:

https://www.speedrun.com/alien_swarm_reactive_drop/thread/7y6kz

"technically not cheating"

We never said that. The main reason we are fixing certain glitches, is because a small part of the community is abusing it in ranked games.

The glitches were removed, the two convars were added by request later. Technically, they are marked fcvar_cheat and are only usable in custom challenges, like the speedrun one.

Regarding speedruns, we don't want to interfere too much in what is a legit or not. However, if we can help to support speedruns in a more easy way (like the convars), we are happy to do so.