There are 2 basic arguments against it.

The first is the cost. No ST3 loves to throw around the $54 billion number because it is admittedly very large. But that's split across ~3 million people over ~3 decades in one of the most economically vibrant parts of the country. And what we'll get for all that money is huge. Many miles of expanded light rail, an entire second transit tunnel downtown, BRT bus rapid transit) lines all over the place and more.

The second argument against it really is still about the cost. Opponents will tell you that we just need to put all this money into BRT because it's so much quicker, cheaper and more versatile than rail. I've already spent hours of my life typing out long explanations for why this isn't really true so luckily just this morning I found an article that backs it up.

So basically if neither of those arguments convince you, vote yes. (Please please vote yes)

Also, if you haven't completely abandoned reddit and want a forum that isn't a complete shit hole (yet) check out /r/seattlewa. The moderating is far far less heavy handed and the conversations aren't as toxic. We'll see how that changes as more people join in.