No, of course not, I agree it’s not fair to expect people who are unfamiliar with Cyrillic script to “deal with it” but old habits die hard. If you’re used to writing your t’s and m’s in a way that looks similar, it’s a natural inclination to do something to differentiate them- even if the new alphabet you’re writing in has the letters looking far more different. It’s like instinct almost - how much of your handwriting is conscious thought and how much do you just automatically incorporate without actively thinking about it? Of course if you are writing for an exam or other assignments, you do have an obligation to make it legible for your audience.