Sarcasm is an adjusted stress reaction.

"NOW I SHALL PUT ON "BECAUSE WE WANT TO" AND DANCE!"

OH GOD OF ISRAEL WHY WHY WHY *dives out nearest window, realizes impact of gesture somewhat blunted by being on first floor, shakes dirty half-melted snow and dead twigs from hair and slinks back inside*

"Likewise, but my vague reading extensive research tells me that no one would have thought twice about it back then, on account of lesbians not existing and all."

If Joan Aiken didn't want us to ship them, she would never have made one of them a bold, enterprising, fiercely protective tomboy with a trigger temper and crack shooting aim, and the other a gentle, delicate, ladylike little orphan in need of emotional succor. She was totally askin' for it.