Mr. Monk Goes Back to School - S2-E1
Factual error: In the cold opening, Derek said that his wife is very smart and got a 1680 on the SAT. This episode takes place in 2003, the writing portion that was added to make the max (2400, not 1600) was in 2005.
Answer: Stottlemeyer was already upset after the phone call. He was trying to get "Kevin" (who would have to be a judge, but no further character information is given) to issue a restraining order with no evidence of needing one, except that Adrian Monk said she needs one. Kevin said he would need to "sleep on it." So it's clear they've been trying to provide protection and unable to get the results they need, which seems to be based on no one trusting Monk the way Stottlemeyer does. He's just angry that they failed to protect Linda despite all their work. Although it does feel like a scene was cut, or altered, from the show that shows the futile attempts to protect Linda which built up to his outrage.
Bishop73