Direct lift from the BBC website:
What Pochettino said - Mike Dean's report in full
"At the conclusion of the game I was approached on the field of play by the Tottenham Hotspur head coach Mauricio Pochettino and some members of his coaching staff, including first-team coach Jesus Perez.
"Mr Pochettino acted in a very irresponsible and aggressive manner. He wouldn't stop saying 'you know what you are, you know what you are"'. I asked him to explain and he repeated 'you know what you are'.
"I then said on numerous occasions to go away at least 10 times and he wouldn't get out of my personal space and then aggressively pointed his finger just a few inches from my face, again saying 'you know what you are'.
"Mr Pochettino then left me alone and left the field of play. When I reached the tunnel he was waiting at the top of the stairs again saying 'you know what you are' and had to be escorted to the dressing room by security staff from Burnley."
No conspiracies - choose not to believe Dean if you like. It sounds totally plausible and from the video you can see him saying "go away", multiple times. The manager crossed a line. Should know better being a former player. The only excuse was "heat of the moment" having just lost - but even that does not justify it.
I'd argue that if he was on the touchline on Saturday, the result MAY have been different. In the stands for Liverpool as well.