Why Do Mainers See This Sign and Then Race You?

This drives me crazy. No pun intended.

This happens to me every single time this sign pops up and two lanes open up temporarily. This sign usually pops up on a hill.

I notice it a lot on Route 26 from Gray into Oxford. There must be five separate times that the one lane opens to two lanes, and it's a chance to get around cars that are just moseying along. I'll kick it up and head to the left lane to pass, as the car veers to the right. And then it happens. They speed up. Then I speed up. Then they speed up, and pretty soon, I'm going 70mph in a 55!

Several times, it's happened where I'm not gonna make it past them before the lanes merge back into one, so I will get behind the car that wasn't about to let me pass. And no sooner do I diligently pull in behind the racer, that he slows right back down to 55 mph.

Oh, that burns my biscuit!

I would be okay if it was just one person who was being difficult, but it's not. Every single time I come upon the 'Slower Traffic Keep Right' sign, this happens! Does my maroon Kia Sorento invite drag racing? It's a step above a minivan!

So help me out. Does this only happen to me, or do you notice this also? If I'm in a particular mood, I have to seriously gun it to get past someone...in the slower lane! Just thinking about it is getting me all worked up again.