"Reset Current Branch to Here" on past commit in local branch - lack of expected effect.

I make some accidental change, that I wanted to undo, with entire branch history, after previous commit, to which I tried to hard reset current branch, but in response, although event log show "Reset successful" message, entire branch history in git tab remained intact, unlike what happened here: https://intellij-support.jetbrains.com/hc/en-us/community/posts/115000713344--Reset-Current-Branch-to-Here-on-local-untracked-branch-commit-history-lost- . I wanted to get rid of the entire branch history after one commit, why can there be no effect?