"harmed" seems like an odd choice of words. The leaks made public a lot of exceedingly unflattering facts (and perhaps illegalities) that put the DNC and Clinton in a very different light. AFAIK, few or none of those facts has been refuted. To me, it looks like the leaks were a great public service.

(I have not much doubt that one could find a similar cesspool on the RNC side.)

The effect of the leaks would have been rather minor if all involved would have just issued a mea culpa and fired the head of the DNC outright. Instead, it felt like they just told us all to suck it up.