I disagree. If 99% of all planets with life only have microbial life on them, why would you think microbes have the same chance of finding us as we have of finding them?
Secondly, it'll be far better, not to mention cheaper, if we can detect and study those life forms with fancy new telescopes, etc., than addressing the issue by putting men in veeeeeery expensive starships and sending them to the stars.
You are not going to explore “mircobial life” on some planet billions of miles away, WITH TELESCOPES.