It is true that trading is very fragmented into secondary markets - but note that this is primarily working against short sellers: they'll statistically have fewer chances to hit buyers in the pools they might be using, and even if their trades are aggregated and effectively anonymized, their broker/market-maker is required to mark the transaction as a short sale and there's few incentives for market makers to break regulations for short sellers, only for the very sparsely reported, low value short sales data is distorted even more ... So the fragmented dark pools make it more likely that a short sale ends up being posted to the main NASDAQ trading book. They don't really care, because they are never identified individually.
Shorts are perfectly fine with the current regulations, which doesn't require the identification of short sellers and where the 'uptick rule' was eliminated. In Europe short selling hedge funds were up in arms (and lost against the regulator) when they were required to report short interest above ~0.2% levels a couple of years ago.
Yes, short sellers are the bogeyman in Tesla circles, and it's partly justified due the Chanos/Cramer style negative news fabrication machine - but in the general scheme of things they are maybe 10%-20% of the daily transaction flow - the other 80%-90% of Wall Street generally watches over their own interests and has plenty of influence at the SEC and FINRA too.