This restriction happens on any stock with significant moves and it's not a choice made by people or a team or whatever it's just a market function of the TSE or whatever. Essentially, to shortsell or do options or whatever, anything other than buying or selling what you own, requires a second party to loan the stock to you, or agree to the options contract, or whatever trade you're doing. You can't physically sell something you don't have, so they loan it to you and get interest. When you sell it, you plan to buy it back at a lower price, then return it to the party you loaned it from. The one doing this loaning/contracts is usually some institution, almost always backed by other investors, ie, for this institution to avoid needing to hold a bunch of bunk stock, they just ask other investors if they want to loan the stock to them for a small interest, many stockholders who have over 5% and are seemingly just holding it? They're actually loaning it so others can shortsell or do options, or they're using it as asset collateral for traditional loans. They're not just sitting on it waiting to sell (though most contracts are quite agile and will allow you to sell portions in case of upward movement to payback, or readjust the allotted collateral, etc).
When this restriction comes up (there are like 5 different types of restrictions, maybe more), it's because there's physically not enough stock to loan out for shortselling, ie not enough holders are loaning their stock out. This is usually because shortbros all gang up on a stock that's crashing to make easy money, but it's like first come first serve, there's a limited amount in circulation. Of course you could also make a private contract with a large holder to have him specifically loan to you, without the TSE or whatever as the middleman, but these kinds of investors usually start talks in the millions (USD), so the average joe stock investor has no chance. Usually this restriction will lift within a few days as things balance out, maybe interest rates get adjusted to incentivize the holders to loan to TSE, or the shorters find another stock to gang up on or something.
Not like you shmucks will understand this post tho so I just wasted my time typing this....
