I was a technician doing industrial microcomputer repairs with that v=ir mentality and life got impossible. Somehow I found it in myself to pray for faith and was rewarded with a satori experience. That's more than 30 years ago now. My life changed a lot.
What's v=ir mentality?
Being "v=ri" or having a "v=ri" mentality means not asking too many questions or not bothering with details or nuance. The meaning is contextual and depends on the delivery.
"That guy is v=ri", means a simpleton, without nuance or character depth, rigid, or extremely effective. It can either be a compliment or an insult, depending on the delivery.
"I was hungry and found a sandwich that's a week old. I was like v=ri" (meaning the person ate the sandwich withtout asking too many questions).
It also means not bothering to understand things and blindly following a rule all the time. No questions asked.
In the context of the comment, I believe it is repairing industrial microcomputers with a multimeter and a soldering iron, checking continuity, replacing parts, without digging deeper.