that would be a fair point if the guy was even playing... this is more like if someone with auto aim and wall hacks was taunting you with emotes or the chat in a first person shooter game...
The taunting feels a little cheap coming from a character that is basically a video game player using cheats or pay to win mechanics....
You're viewing this from the wrong perspective. You're viewing it as actual taunting, something done separately from the actual combat as a form of player-to-player communication.
In reality, the taunting is a fundamental part of the cheat skill. Auto-mode maintains full knowledge of every part of its environment, and it leverages this knowledge to work with an manipulate its environment in order to guarantee a desired outcome. In the case of combat, "its environment" includes opponent it's fighting against, and it manipulates said opponent the same way it does the rest of the environment, which includes taunting them to direct their actions.
In a sense, it's more like a TAS than it is a mere aimbot/wallhack combo: It's a sequence of precisely calculated steps and "inputs"/actions sequenced together in a way that guarantees a desired outcome, and each taunt is simply one of those steps.
Now, granted, it's possible that there are other sequences of actions that would work to guarantee victory that
don't include taunting. I'm sure that most battles have more than one route to victory and, given that auto-mode seems to also protect those that Klaus desires to protect (or, at least, leaves them out of the battle) without extending that consideration to Gaine, it seems likely that auto-mode has a degree of agency (and possibly even personality) regarding exactly
which route it takes to success (that, or Klaus's own desires/intent influences how auto-mode approaches a problem, which is possible). In that case, the choice to use a sequence that includes the taunting is definitely a bit on the cocky side, but the taunts themselves are still an integral part of the plan for that chosen sequence.
That said, it's also possible that auto-mode is simply choosing a truly optimal path to success every time, and it just so happens that those optimal paths include manipulating enemy behavior via taunts. This would also mean that it's just a coincidence (an author-enforced one, of course, but let's set that aside for this analysis) that, so far, none of the auto-mode sequences have involved harming or sacrificing innocents and/or people Klaus cares about (since Klaus hasn't been given the opportunity to input auto-mode parameters like "protect party members" so far when starting auto-battle), while still sacrificing Gaine in this particular battle.
It feels unlikely that this is the case, of course, but it's still a possibility.