MC is right in his speech
The founders of the nobles houses were great people, and their decendants use the actions of their ancestors, without doing anything themselves.
Just because your great-grandpa killed a dragon, does in NO SHAPE OR FORM mean that you can take credit for it.
If you get a "random idea", make a small portion of it, and taste it, so you don't ruin the whole dish if it fails, and if it's succesful/tasty, you can make it like that next time.
The whole "she just came and attacked him without reason" is far FAR *FAR* too little information, there must be SOME reason why she did it (will most likely be revealed later)
My theory is it was a doubleganger, to blame her or he was secretly a bad guy.
Workplaces like that, should hire 1-2 people to clean and such, to ensure it dosen't pile up.
The easiest way to clean up, is to prevent it to get too dirty to begin with.