My opponent has Valgavoth, Terror Eater on the board with Swiftfoot Boots attached. On the board I have 5 creatures as well as Sothera, the Supervoid. I have a 3/3 creature attack, which is blocked by Valgavoth (killing it), but they did not have to exile Valgavoth.

My understanding of the rules is as follows, please let me know if I have something wrong.
- Blocking my creature caused damage which kills it, moving to the next step of going to the graveyard. If it had not died at this step, it would never engage going to the graveyard
- Valgavoth triggers and instead of going to the graveyard, my creature gets exiled
- Sothera would then targets my opponent, who then has to choose a creature, so the hexproof and ward on Valgavoth should not come into play here

Thanks!