"No business"?
It's not like the "superhero community" in the MU has ever had any
hard-and-fast rules about "who's
allowed to recycle a previously-used heroic alias, and who
isn't!"
When Johnny Storm started calling himself "The Human Torch," he'd
never met Jim Hammond; he'd just read some old comic books about his illustrious predecessor! Johnny didn't feel any need to fill out any paperwork in triplicate, "formally applying for permission to use the name," and then submit it to a committee and wait six months to hear back from them. His logic seems to have been: "It's a perfectly good heroic alias; nobody else has used it in years; it reflects the nifty new powers I just acquired; so why not grab it for myself?"
Jim Hammond himself, when he came back onstage as a "regular presence" in the MU in the late 1980s, seems to have accepted the situation calmly instead of screaming: "You had no right to grab my alias without my permission!"
Likewise, when Danny Ketch became the new "Ghost Rider" in 1990, he'd never met Johnny Blaze (although he did later). Danny's solo title lasted about 8 years.
Warren Worthington III never apologized to the Golden Age Angel for swiping his alias; the synthezoid known as The Vision never apologized to the Golden Age Vision; Natasha Romanoff never apologized to Claire Voyant (the Golden Age Black Widow); Peter Parker never apologized for the fact that long before he became "Spider-Man," there had been a mad scientist called "Spiderman" who died fighting Madeline Joyce (Marvel's Golden Age Miss America) . . .
So why should
Monica feel guilty about reviving a heroic alias which nobody else had used lately?