Your point sounds reasonable, but there's a good reason to block first sale.

Suppose I run a firm that sells custom men's clothing, that has a patent to, say, change color and temperature at the wearer's preference. Each outfit has to be personally tailored by a professional designated by our company.

Now, perhaps a high-end men's clothing retailer begins selling my clothing and tailors it in-house. The quality is comparable and they compensate my company. So far so good, right?

Well, what if quality isnt comparable? What if the stitching was improperly done and felt too tight, or unraveled over time? Even if the customer knew that the "re"-seller wasn't an official associate, the damage to our brand would already be done.

And that's why first sale should be at the discretion of the patent holder.