Alright. Allow me to rephrase my point more succinctly so you will not purposefully misinterpret it.
Fortuna has been out roughly for 142ish daya so even with an MR1 repcap if you maxed out every day since release (which would take maybe 10 minutes a day at that low of a cap) you would have 282k reputation. Which of course you only need 240k rep to make Old Mate.
Now I'd almost bet dollars for dimes the real reason for your complaints is, as you stated, you don't have the rank yet. Did you voice complaints about the challenges requiring sorties? Remember those have an MR lock on them.
Call me a white knight if you will but I am not defending DE so much as just disagreeing with your sentimentality involving including everyone in all content. IF this were a short time limited event where you HAD to have this to max out THEN I would be firmly agreeing with your viewpoint. Yet missing this challenge will not put a player out of the running for the end of Nightwave nor does even missing a few of them.