Do individuals like this hurt or help their respective styles or martial arts in general?
My opinion is cross-training is great to test ourselves in a different environment. No intrinsic downside.
Answering the question, 'individuals' like that may help or not martial arts.
Pros:
- brave enough to face an experienced figther (and put it online).
- Tried to improve* Aikido. (read tried to make is style work against controled [but real] opposition; would recomend it to everyone).
Cons:
- He put himself in a situation were Aikido has little chance, does not matter the praticioner, isn't it? Aikido in gloves?! Against someone that does not commit with, or telegraph, every attack?
- He lost even before trying, due to his mindset.
- People may overgeneralise and think X or Y martial art is useless and only MMA works.
To finish, if X martial arts guy fights a good MMA guy in MMA rules, of course he looses. Mayweather or Mike Tyson would loose against a current MMA fighter (well, at heavyweight we never know...). If a trained MMA guy goes to a boxing match or BJJ competition and wants to win, he most fight lower ranks. Last point, MMA also works against the practicioner (more than other 'weak' styles); they are all injured at some point if not living with injuries all the time.
*What I think on Chinese martial arts, is they are too much complex (and with a complex history), so people hardly can understand and apply it in most scenarios; and it may apply as well to Japanese martial arts and Aikido. Maybe
his Aikido is weak, to start with (up to the wrong scenario for Aikido and wrong midset for a competition).