Grace

So now we can all have another laugh at Microsoft's expense. Some unsuspecting clod in HR apparently tried to recruit Eric Raymond, one of the most vocal and outspoken critics of Microsoft, and a prominent figure in the FLOSS community. Oh, the bitter irony. Unfortunately...

Unfortunately, Eric takes the opportunity to fire off an arrogant, childish tirade and makes the whole community look bad by association with this unprofessional behaviour. Anyone who knows me knows my views on MS. But honestly, the letter was obviously boilerplate text, and the guy sending it presumably clueless. But replying that you are going to piss on them just gives them more ammunition to point to the FLOSS community and say "look, what a bunch of long-haired gits!"

If it were me, I would probably opt for something like this:

Thank you for the offer, but I must decline.
Perhaps you might read some of my articles?