My take:
He can claim he is proud because he acknowledges their work and - as the rest of the work - it influences promotion and raises.
He enjoys and rewards the positive impact this work has for the company image and the skills of the employees.
I can understand that, I just disagree that to be a better employee one should also devote their free time to an activity that directly influences one's performance review at work. This is definitely a good deal for people who enjoy doing OSS work on their own time-- but it feels wrong and not fair to those who don't want or don't have time to put the extra hours for that.