They just adapt to their opponents... if you're too tight, they will 3bet your wider, double and triple barrel you and use your stats against you [eg your propensity to open light, then fold to 2 barrels or a triple barrel] bot programmers are smart
At a minimum - In SNGs the bots are ICM wizards... Playing GTO Poker. i.e perfect pushbot / call poker. When you consider that htey can also use player history tracking - they can take exploitation a little further because they know the players ranges and plays with specific stack sizes based on observed history over a large sample size. [this is the edge that anonymizing player screenname will negate, but not the 1st bit, nor the ability for bots to play on the site.. obviously]
Cashgames they will exploit your stats [eg playing too many hands OOP, defending button too light etc] and you might end up with a couple of bots on your table, cardsharing + squeezing you out of pots by reducing your equity [more players in hand see flop = less chance your AA wins for example].
This is why I stick to MTTs - the bots don't seem to play MTTs from what i have seen.