The bad thing about them is when you mow, they just lay over and spring back up higher than the grass you just mowed. Then 3 days later, they have grown 3 more inches. 90% of the green in my yard is onions. They are real bad in early spring and again in the fall, but other than that they are not noticable during the summer. They are only in the front yard. I fertilized the front yard a couple of times when we first moved here, Maybe that's what made them take over.
The only way I could physically remove them like the guy said in the video would be to get a bulldozier in here and cut the top 6" off the entire yard. They are that thick.
I've heard of ramps, but I think they only grow in the mountain areas here.