Domain specificity of "weak link"-hood, as well as the compounding of innocuous, sub-symptomatic "weak links":

Carpenter Tom is a hard-worker, great husband, and community leader. And he voted for an autocrat, against his explicit interests (benefits from ACA, benefits from undocumented immigrant labor, benefits from special-ed resources for his kids) because he dislikes keeping abreast of current events (poor reading speed) and made his decision based on a misunderstanding predicated by, essentially, a game of telephone across his personal network that warped facts about the candidates.

He's a "weak link" on the subject that counts - the matter of the vote - but otherwise an upstanding member of the community. You're going to disenfranchise him?

I sympathize with the rest of your comment. I do think it's a bit naive to think that these programs help even of a fraction of the poor kids they should be reaching. They seem to mostly be a way to section off semi-affluent kids in "lesser" schools (e.g., parents who can't move for work or family reasons).