Bots are real, and are deployed on every site out there. Some are so well programmed and disguised that they are extremely hard detect.
whether a site does or does not itself implement bots, no one will ever know.
( If they are, and it ever got out,
online poker would be dead forever. No one would ever trust computer based poker, and the game would be damaged beyond repair. )
As for Sites rigging the deal, that is another matter.
A site would be stupid to alter the dealing algorithms to favor one player over another. however for the purpose of combating Bots, collusion, and game manipulation a site might implement software procedures that level the playing field.
We all know that sites make money by charging players a small percentage for using the services of the site, but we also know that if new blood isn't brought in, the site would be bled dry by the regs, cheaters, and one timers that would hit and run.
( and possibly many other more ways )
If new players have little to no chance of winning, or keeping some portion of what they have deposited for a reasonable amount of time, no one would want to play.
So lets say a site programs a way for new/lower skilled players to gain an advantage over the higher skilled players, such that the lower skilled player is given more time to play and learn. Plus a lower skilled player is given a "Win" once in a while, so as to keep them coming back for more.
In this way, a site is keeping the highly skilled players in check, while keeping the lower skilled/recreational players interested.
How sites would go about doing this, wish i knew. I wouldn't be in the same boat as everyone else.
And NO, a losing player I am not!
I am a average player that is working on getting better, and fully understand that players go though cycles of wins and losses.
I'm also smart enough to realize what is going on, and use that to my advantage when needed.
As the old saying goes: " Work smarter, not harder!"