The road to hell is paved with good intentions, or so they say.
Friends who play cupid, whilst their intentions are thoughtful, what they fail to see is that if it doesn't work out, or ends up being one-sided, it just creates one hell of a hot mess for everyone to deal with.
If two people like each other, it will happen on it's own. However 'encouraging' two people together will most likely end in people just being put in an awkward situation. And no one wants that at a Sunday BBQ.
Avoid the awkward. Don't set up your friends.