First:
Assange didn't/couldn't pick and choose the information given to Wikileaks. He was a publisher, not a commentator or even an author of the content on Wikileaks. They published what had been provided to them. If you have a problem with what Wikileaks was or was not given to publish maybe you should have provided them some stuff you'd rather see.
Second:
If you have questions about what Wikileaks has or hasn't published I highly recommend going and perusing the site for yourself. There is a lot of content there that never got as much public attention as the DNC/Podesta emails but are equally as important and illuminating. May I suggest beginning with the 'Vault 7' CIA leaks? Yeah they're from 2017 but they're still relevant... just like the DNC/Podesta emails.
Free your mind and your ass will follow.

Assange himself said he didn't "publish" dirt on Trump because he did feel the need to. He as "publisher" seems to have picked and chosen what he "published". I know what that says to my freed mind, what it means to you partisans and other conservative sorts I can not say, but given your statement it's an easy guess.
I have no dog in the race, as the Earth saying goes, but as an objective observer it is evident that "publishing" dirt on one but not another prior to an election could represent an expression of bias.