OK, Chrome - Firefox - Safari.....not sure about Edge, but it's got to have something like the javascript console.....
Basically, these code snips will allow you to mass upvote (or down vote) for an individual user or stream.
1. Navigate to the user or stream you want to up or down vote. For a user, also click the button to see their "Latest Submissions"
2. Open developer tools (F12 in Chrome and FF) - navigate to the Console (Javascript Console)
3. test that you're in the right place by typing alert('hello') into the console, this should display a "hello" popup/alert message. If you see that, you're in the right place - close the alert
4. The replies below contain the code you need to accomplish this. Basically, paste the code and press enter. It will up (or down) vote all of the memes on the current page and click next. On the next page you should be able to press the up arrow on your keyboard and enter to up (or down) vote all of the memes on that page - rinse and repeat until you get to the end (or until you get bored)