The Pharisees were not themselves present at the dinner with the tax collectors and sinners, but probably passed by to see what was happening, so that they could confront not Jesus himself, but his disciples, with their rebuke of his conduct. Later, they would do the opposite, reproaching Jesus for his disciples’ behaviour (Matthew 12:2, Matthew 15:2).
No, the Pharisees were not present at this dinner, but perhaps purposefully passed by the home of Matthew around dinnertime to see what was happening. Following the meal they then approach the disciples to accuse Jesus.1 Notably, they don’t approach Jesus directly, as their strategy is to try and embarrass the disciples, suggesting that he may be leading them to apostasy from Israel’s God.2 Later, however, they would turn the tables and approach Jesus himself, this time with an accusation against his disciples (Matthew 12:2, Matthew 15:2).3
11 And when the Pharisees saw this, they said to his disciples, “Why does your teacher eat with tax collectors and sinners?”