Townsend described it as a “character assassination” and called on the authorities to clamp down on coaching staff who try to intimidate opposition players and referees from the sidelines.
Erasmus reprised his “water boy” role against Scotland, allowing him access to the field of play to hand water bottles to the South African players, a ploy he used during the summer series against the Lions.
Townsend believes rugby’s values are being eroded by such behaviour and also expressed concern that Erasmus’ criticism of the referee Nic Berry after the first Lions Test was not dealt with sooner.
Erasmus has been banned from all rugby activity for two months after six charges of misconduct against him relating to criticism of match officials on the Lions tour were upheld.
He is also suspended from all match-day activities, including coaching and media engagement, until September 30, 2022.
Townsend felt the sentence was fair.
“That was a really bad episode for our game,” said the Scotland chief, who was the Lions attack coach in South Africa. “I was there at the time so I experienced what was going on.
“I have since spoken to Nic Berry about it and he went through a really tough time and so did his family. That was a real shame and a pity that these things can happen in our sport. I don’t think it could have been allowed to continue.
“Those antics - we can’t fall into that trap of winning at all costs and putting pressure on individuals.
“It has been a while for that decision to come. That would be my only frustration, that it has taken so long to come to this decision.”
“I wasn’t really aware of it at the time but someone showed me a video of him making comments about one of our players, a character assassination or sledging or whatever,” said the Scotland coach. “That’s not the role of coaches; it’s not the role of anybody on the sidelines to be doing that.
“If we want our sport to go down a different route then we allow these things to happen. That was really disappointing to see and I know it wasn’t the only incident over the weekend, over that game.”
While welcoming the punishment meted out to Erasmus by an independent misconduct committee on Wednesday, Townsend felt the matter should have been dealt with in the summer.
“I feel that whatever happens around a game, whether it’s a player or a coach or someone related to the game like a physio, decisions have to be made more quickly,” he said.
“I would urge World Rugby to make further changes. Why do we need coaches on the sidelines? If they are on the sidelines they have to live up to certain behaviours and values that we pride in our game, which sadly I felt over the summer and since then have been lost.”