What you're doing with this:
[[!getResources?
&parents=`0`
&where=`{"createdby:=":[[!+modx.user.id]]}`
&tpl=`Search Results`
]]
is filtering based on the currently logged in user, not what you passed in the url. Also you're filtering on createdby here, but passing publishedby in the url - those could be different people, so could lead to weird results.
I would go back to your link generation and change it to this:
<a href="[[~27? &author=`[[*publishedby]]`">[[*publishedby:userinfo=`fullname`]]</a>
That will make the urls a bit uglier as it uses the ID, but it makes the filtering easier.
Next, install getUrlParam from the Package Manager. This is a snippet that will let you easily access GET params, so you can grab the passed ID. Getting the author id from the url would look something like this.
[[!getUrlParam? &name=`author` &int=`1`]]
Combine that with your getResources call, replaceing createdby with publishedby for consistency, and you get this:
[[!getResources?
&parents=`0`
&where=`{"publishedby:=": [[!getUrlParam? &name=`author` &int=`1`]] }`
&tpl=`Search Results`
]]
And you should be good to go.