I'm just your "average Joe", and me and all of my average Joe friends, and all of the rest of the average Joe's out there are not going to use bitcoin if it takes more than ten minutes for a transaction and high fees will soon price alot of people out. Those are the cold hard facts. You can kiss the fabled "mainstream adoption" goodbye.
Nope, these attacks are not net positive.
How many people join bitcoin in a day? 5000-6000 tops?
Well, by doing an attack this scale probably worth millions of $$ to do, actually they are donating that money away to miners and it benefits existing users more than what we would lose over that 5000 people not joining.
So the bottom line: Attacking the bitcoin network is always a net loss for the attacker and a net win for the network.
Not to mention it helps developers give them new ideas to protect the network with, which can be used for defense against future larger scale attacks.
I don't think this is an attack or spam. This is just regular transactions that have what used to be regular fees, that aren't getting confirmed because there is not enough room in the blocks for them all. Raising fees won't fix that. Only a block size increase will do that.