It's not ageist. It doesn't say People who are 50 need not apply. From reading this job posting, someone who is 80, worked as a mechanic, a waiter, a clerk, and then picked up some newfangled technology might qualify.

Besides the whole Agile not being codified for more than 12 years thing, if you've been out of the loop managing for 12 years, they say they don't want you. Part of the process apparently involves showing that your technical skills are still there.