I was and still am against the downvote button as well. If someone does not share another poster's opinion, you can simply ignore it and do something else.

That down-vote feature just brings too much negativity to the table instead of positivity, IMO - and the "meme downvoting" of the first post is another good example of this negative impact.

You could try to log in with a different default browser, e.g. Firefox or Chrome, without any extensions enabled. Also, check your security software if it interferes with the login process.