Trading was not suspended on the market, but buying was suspended by Robinhood(selling was still available). Robinhood was no longer being paid to sell GameStop stock, and in fact was being charged money to sell it. This meant that Robinhood was losing money, and fast.trading was suspended on a stock where large institutional positions were losing.
this was not a disinterested action for the health of the markets.
the GameStop stoppage was evidence of clear bias and insider trading on the markets as a whole.
There were some large institutions on the other side of the deals, but there were also many very rich individuals. Whoever they were, they were no longer willing to be on the other side of the deal.
Insider trading is a bit of a stretch. The "smart money" lost a lot of money, because they did not understand GameStop. That is the opposite of insider trading.
There is a problem that no one thinks about. Even if you do work out a way to make huge amounts of money, the rest of the world does not need to continue to provide you that way. With card counting, the casino can just ask you to leave. They do not need to allow you to continue gambling if they are losing. If you start making huge amounts of money at online poker, that will drive other online poker players away, and the online poker company can drop your limits down to a few pennies. You will still win at online poker, just win less than a dollar an hour.
The "smart money" ran into the same problem. They could not find anyone willing to take the other side of deals with them. The reason Robinhood exists is to funnel "dumb money" into the market to be the other side of deals. It is free, because everyone is just happy just to have "dumb money" in the market. When the "dumb money" turned out to be smart once, the "smart money" chose to walk away from the table.