I have no horse in this race, but Europe in GW2 is a bloodbath (seriously, anyone else want to add yet another a convair/vickers into a 200 seat route that now has 2,000 daily seats...and yes someone does

). GW2 itself is a challenge as tried and true strategies are useless in this game. The Dutch guy had a fleet of comet 3s and 707s. At the end of the day, buying these planes with a major international airline in AWS prior to 2/2019 was a decent strategy. Now we will all think differently for the next games.
If the sales were done in the parameters of the market and game limits, then so be it. If the player opts to exit and liquidate planes vs taking loans to restructure, then so be it. I might be off base, but it would be nuts to restart and lease 707s unless you like restarting repeatedly...Dubai, jfk, lhr or otherwise.
It's one thing to challenge everyone to new challenges, but micro managing the game to this degree is ridiculous.
The best player ever IMHO was a guy in one of my old, off-the-majors-grid, alliances who based in Lagos Nigeria and ran a small fleet of commuter planes. He plowed all his money into buying and selling planes starting in the mid 1950s...alliance or free market. High demand planes, and your alliance discount was the max price if he was in a good mood...often it was a "no" because he could max out the price to the highest bidder. By the end of game he was buying and selling fleets of 777s and A340s from Nigeria for pete's sake (

to you mr. PKKO). If that's your strategy and you can pull it off, then more power to you!
All that to say, if the actions are within the parameters of the game, then get over it!
Hopefully you got a nice revenue boost when the Dutch guy went bankrupt. And frankly, the Dutch guy that was your competitor f'ed up and went bankrupt so now you should capitalize on it. If there were shenanigans and he rebased in AMS...then there's probably something there, but If he opens in a new base, then consider it your opportunity to get ahead.
At the end of the day, it's a game with fairly decent rules. i think (well fairly certain

) I was the guy that triggered the overcapacity rule in the early 2010s after the howls from someone. Fair enough, Sami is pretty good at arbitrating...in this case the overcapacity rule, with ability to limit seats on planes after I threw my own hissy fit about not being able to fly routes with large planes that could still be profitable...and then the zen balance and life/AWS moves on for the better.
My reaction when the Dutch guy went out was damn, another Comet strategy victim. This seems way overblown...and if he did offload 707s, to get them back for a quick start somewhere else, then I still don't see the issue other then waiting for his next death spiral...seriously, restarting in GW2 with 707 would be punishment enough.
Sorry for the long post / rant but to recap,with no horse in this one,I don't see what the issue is here.
If the anti trust fellow was targeted by the alliance, then Sami should determine appropriate actions to keep the game play fair and prevent bullying.
If the sales in question are in the Alliances limits to buy /sell, or non alliance then that's capitalism folks. If you go out and exit and liquidate the fleet then so be it. If the planes are bought low and used against you with a massive 707 invasion into AMS then raise a fuss to SAMI...but if said 707 move on to fly JFK-LHR...well good luck to whoever thinks they can make them work.
About the only thing positive I can say about gw2 so far, is thankfully I didn't get in the 707/D.C.-8 queue as fuel prices, winds, lack of demand and who knows what else there is to complain about are way out of alignment in this GW...but it's still fun enough for now