As a wirehead advocate, I want to present my response to this as bluntly as possible, since I think my position is more generally what underlies the wirehead position, and I never see this addressed.

I simply don't believe that you really value understanding and exploration. I think that your brain (mine too) simply says to you 'yay, understanding and exploration!'. What's more, the only way you even know this much, is from how you feel about exploration - on the inside - when you are considering it or engaging in it. That is, how much 'pleasure' or wirehead-subjective-experience-nice-feelings-equivalent you get from it. You say to your brain: 'so, what do you think about making scientific discoveries?' and it says right back to you: 'making discoveries? Yay!'

Since literally every single thing we value just boils down to 'my brain says yay about this' anyway, why don't we just hack the brain equivalent to say 'yay!' as much as possible?