It's not if Israel continues its killing campaign. At best, I could agree that Hamas surrendering would not increase casualties, but I doubt it would decrease them in any way.
I don't think that's a very defensible argument, but if you really believe that our premises are probably too far apart for it to be productive to keep talking about it. I don't think that Israeli attacks on Hamas installations are proportionate, but I don't think it's a mainstream bit of analysis that they're completely decoupled from Hamas itself.
Again, I would say, the Rule of Lord Farquaad applies.