Also retail isn’t really well defined in terms of dollar amounts. there are some extremely wealthy people classified as retail. And they don’t need to be as ultra conservative with their trading as institutional traders because they are trading their own money.
Example: As of market close on Friday, a June 19, 2020 expiration HTZ $3 strike call option cost .55 ($55) and has a delta of .56; if I were to buy a 10 lot for $550, the options market maker would be short 560 deltas and would purchase 560 shares of HTZ to hedge their short call position. This can push the share price up quite a bit if there’s non-stop call buying.
The converse is also true for put options, buying puts from an options market maker forces them to sell the underlying to delta hedge.