You're right. I don't want to leave people thinking that non-profits are always right and should never be questioned or given outside advice. Perhaps that language was overly strong.

Is there a modification I could make to improve it?

I thought the way I phrased the whole sentence made it context specific

Don’t try to out-think the non-profits you support - they wish you were donating now, not just later.

But I could see how it could be construed to be making a broader statement than I intended.

Maybe it could be:

Don’t try to out-think the non-profits you support in this specific way - they wish you were donating now, not just later.

Don’t try to out-think the non-profits you support like this - they wish you were donating now, not just later.

When it comes to donating, don’t try to out-think the non-profits you support - they can likely do more with your money in the present.

Don’t try to out-think the non-profits you support without talking to them - they probably wish you were donating now, not just later.

EDIT: Changed in article. What do you think?

These can be times when contributing one's time can actually be more useful than the equivalent amount of money. Case by case, of course.