How many times do you want people to tell you that everybody knows that Kolmogorov complexity (KC) is only defined up to a constant?

This does not affect the results that people use KC for, like the incompressibility of most strings.

That's what my second post linked above addresses. I think it does affect the 'incompressibility of most strings' result. I'm fine with not rehashing the argument though, unless you're keen to do so :)

What you need to do is produce a programming language L such that the existence of incompressibility of strings becomes false, e.g. contradict Theorem 2.2.1 of Li & Vitanyi.