An honorary degree is not meaningless. It is an official degree typically bestowed by a bona fide institution (that also has non-honorary degrees). It is also given to individuals that had a deep impact in some area, arguably a much deeper impact than any freshly graduated PhD student has.

So it doesn't bother me if any of them signs Dr. Bill Gates, Dr. Billy Joel or Dr. Clint Eastwood as they, in all likelihood, are important in their fields, much more than I was when I submitted my thesis.