You're wrong on this one. It is a solid comparison. During the French Revolution's heady days they did change the names on the calendar but soon changed back. The abbreviations are just names and most Jews think no more of using AD and BC than Christians do about tossing around the names of Pagan Gods. Most Jews in America go to public schools or secular private schools, not Hebrew schools. Most Jews just don't worry about the names of calendar parts.
It would be very hard to change the days of the week and the names of the months, but why not? Old Roman deities seem to have little place. Let's try this. It would be super easy to understand, and wouldn't offend anyone, since they're just numbers. I say we should go for it:
Firstday = Sunday
Secondday = Monday
Thirdday = Tuesday
Fourthday = Wednesday
Fifthday = Thursday
Sixthday = Friday
Seventhday = Saturday
Similarly, for the months:
Firstmonth
Secondmonth
Thirdmonth
Fourthmonth
Fifthmonth
Sixthmonth
Seventhmonth
Eighthmonth
Ninethmonth
Tenthmonth
Eleventhmonth
Twelftmonth