It might be possible to pass it as part of the uri, but you do not want to do that because it would create a second url representing the same resource. Basically, you want to have one url per resource to make the API easy to use, and for things that are actually queries it is better to use parameters.
Here is a simple example to illustrate the problem by adding voting to the user resource:
Which one is the correct one? Software developers would guess the first one, but machines would be clueless. And you would have to implement both routes to be consistent, then you would have to document it, and then you would hate programming