I am unfamiliar with pronouns, how is the "you" here rude?

Saladofstones said:

I am unfamiliar with pronouns, how is the "you" here rude?

Just guessing, but I think just saying "you" rather then your name can be seen as disrepectful, which matches her "edgy personality"

The "you" here is originally お前 / omae, as people may know from the Kenshiro meme.

formerly honorific, now oft. derog. term referring to an equal or inferior.

Someone could probably think of an actually-rude English translation for it other than just "you", but I personally don't have any ideas right now.

Japanese pronouns offer a rich variety of shades of respect and disrespect that really gets lost in any direct English translation. I've often seen Chiyo's "omae" translated as "You--!", as if she's suppressing a curse (i.e., she wants to say "You bastard" or worse but is settling).

That said, "Welcome home, you" instead of "Welcome home, master" does get the idea across.