That's the kind of thoughts that clearly draw a clear line between developers and marketing ;)
There is no clear definition of spamming AFAIK, it all depends on user perception given the frequence and the criticity of the content. What we call spamming here, if we talk about showing a pop-up a few times a year can also be perceived called "reaching users and educating them about the values of our community and ways to give-back to it".
The frequency is the same you get from Eclipse mailing-list, of from many mailing-list of products you're using or not, and which have a good retention policy (ie people keep subscribed). So such pop-ups may not hurt as much as you think...
Also, we're talking about the Eclipse IDE delivery to end-users (aka EPP packages). Anyone unhappy with the popup is free to repackage the IDE as they need and according to their ways to support users and Eclipse development.
But anyway, I would suggest anyone serious (including myself) to stop arguing about it as the current proposals seems sufficient ;)