I saw Walmart's web site is selling Lightroom 6 and claims it can be used for 6 users. Does it mean it can be installed on 6 different computers?
You are permitted two activation's per license.
Well unless Walmart has some different licensing built into the Lightroom 6 software that the version sold by Adobe, you will be permitted to activate the serial number on two computers concurrently. This is controlled by the software.
And I highly doubt that Adobe has made a special deal on this with Walmart to allow six activations simultaneously (but of course, it's not impossible that they did).
But you can find out if the software can really be used on 6 computers, buy it, give it a try, and let us know.
I think the Wall Mart description is not correct. It refers to the ability to correct haze, but the Dehaze tool is only available with a Creative Cloud subscription. It is not available in LR6.