Im a noob in speeduns, but why in some games like Half-Life is allowed to change ini file , use console to change framerate (like in this world record ), and they even use mods like Bunnyhopping? (i see tutorials how to "prepare" game by injecting files in game folder )
I dont understand something or why its allowed in "non cheating" non-TAS speedruns? why they just dont type "godmode" in console if they use it anyway - its the same cheating to me. in other word - Why dont just use original game and speedrun it?
You should start by asking the runner directly, or asking the Half Life community in their forums. Just because something seems like cheating to you, doesn't mean it is cheating. The community of the game made the rules for the game, and decides what is and isn't allowed in runs. They can explain the reasoning for the rules much better than the general community here.
I watched that tutorial. The creator explains at the beginning how to install a practice map so you have more space to practice bunny-hopping. I don’t believe bunny-hopping is a mod.
If everyone running something does so by the same rules regardless of what those rules may include then why would anything in those rule ever be considered cheating? They don't use godmode because they decided it didn't fit that particular category, that said if people were to actively start running a godmode category for some reason the same would apply, I don't even think it'd be boring considering just how movement intensive the HL run can be at a competitive level.