I have resisted the urge of promoting my blog for many months, but this is literally (per my analysis) for the best cause.
We have also raised a decent amount of money so far, so at least some people were convinced by the arguments and didn't stop at the cute hedgehog pictures.
Whether that's a problem depends on whether your goal is to be useful to your readers or to keep your readers on your page. It will be the latter if you run an ad-supported site and your only goal is to maximize your revenue. In other circumstances, it might be the former.
Indeed many successful blogs provide lots of useful or interesting links. But these links don't take readers away but actually seem to draw them in! Sure they leave the page - but if it is good they come back to follow more of the interesting links!