I'm mixed about it.
In professional sports I rarely dislike it for several reasons and under several conditions:
1. Professionals, equal playing field, fans may like seeing the starters perform from start to finish
2. We place a lot of emphasis on history and records, so I don't mind it if a team or player is chasing certain records, etc.
3. The biggest reason is we have had some ridiculous comebacks recently across many sports, so it is actually really hard to say with certainty when it is running up the score and when it is just trying to protect against a ridiculous comeback. I know I wouldn't want to be on the losing end of an epic comeback because we were trying not to run up the score, and I don't think there will ever be agreement on when a lead is safe. In professional sports, I generally say that if the losing team doesn't appreciate the score being "run up," then they could also stop trying on offense or forfeit the game. In football, if a team was losing and started kneeling, I bet the other team would return the favor. But you never see that. So if a losing team is supposed to play to the end because anything could happen, why shouldn't the winning team?