"If you gave me that option I would not take it, because it would be a lie that I would receive pleasure from the end of mankind."

Consider the package deal to include getting your brain rewired so that you would receive pleasure from the end of mankind. Now do you choose the package deal?

I wouldn't. Can you explain to me why I wouldn't, if you believe the only thing I can want is pleasure?

Stop moving the goalposts.

Giving additional examples, based on the same principle, isn't "moving the goalposts".

Why to argue against me to you have to bring murder or death into the picture?

Because the survival of your children and the community is the foremost example of a common value that's usually placed higher than personal pleasure.

You think you want more than pleasure, but what else is there?

Knowledge, memory, and understanding. Personal and collective achievement. Honour. Other people's pleasure.

I believe if you consider any answer you might give to that question, the reason will be because those things cause pleasure.

As an automated process we receive pleasure when we get what we want, that doesn't mean that we want those things because of the pleasure. At the conscious level we self-evidently don't want them because of the pleasure, or we'd all be willing to sacrifice all of mankind if they promised to wirehead us first.