That is true now, but remember how far back this was. I was programming Modula-2 on CP/M - our lab standardised on the Amstrad 8512 for control / data acquisition for cost reasons. Early PCs existed, running MS/DOS, so you could probably get Micro-Emacs - I don't remember when that came out. I remember seeing one Sun 3, but they were not common equipment. This was at Oxford. So in brief, it didn't work well with the operating systems of the period.

Can you fix that problem now? Yes, but the window for Modula-2 closed decades back. It doesn't have any significant selling points now.