There are definitely two schools of thought here, and it's unlikely that members of one will convince members of the other to change sides.
Yes, the defender made a mistake. Yes, one can look at it that way. I just don't think calling a foul in that situation fits with the spirit and intent of the rules.
The coach of the team that benefits will think he got a gift and the other coach will feel he got screwed. It just isn't a good foul IMO, but I will recognize that others feel differently. Keep in mind that the people that feel differently are likely to not be the participants or the coaches
Rich