A blanket ban like this isn't particularly useful advice. I2C is perfectly useable in less-than-perfect environments, and LEO isn't really as harsh as people make it out to be. It's really only going to be a problem if you assume that everything operates perfectly all the time, and if you're making those assumptions you're going to have a bad time working on remote systems anyway.

Make sure your drivers can handle NAKs and errors on the line. Make sure you can reset subsystems (probably by power-cycling) completely and your system can keep running. Be ready to deal with stale sensor data or having to do a few retries at times. With these and some good testing you'll be fine with I2C, and really there's immense value in having those attitudes in your system design anyway.

I was a design EE at Planet Labs for 4 years, have sent something like 200 satellites to space, each with literally dozens of I2C devices on them, and supported them in orbit.