I think the page you link to is a good example of why Purism comes across as
less-than-honest. While they avoid explicitly taking credit for disabling the
ME, they phrase everything so that if you aren't paying very close attention
you'll interpret it that way.
For example, your initial post indicates that the Purism article led you to
believe that this is a new accomplishment and that Purism is responsible for
it. When ivanB1975 pointed out that this is not true, you acknowledged that
he was correct but apparently did not feel lied to by the article, perhaps
because it avoided making any explicit claims about the issue.
As far as I know Purism hasn't actually lied about anything, in which case
you are correct that they are not literal frauds. However, they use
misleading language so consistently that it is certainly intentional, and the
tactic seems to have worked here.
Compare that to the language Technoethical uses here.
"Technoethical S3 smartphones are refurbished Samsung Galaxy S3's
pre-installed with the 100% free operating system Replicant. Please note that
while the main processor is running only free software, the modem processor
is running a Samsung nonfree system."
They state exactly what they are selling, appropriately credit Replicant for
their work, and then immediately draw attention to the nonfree modem. They
then go on to disclose the other limitations of the product, with phrases
like "read-only nonfree boot rom" and "nonfree bootloader" in bold so the
reader won't miss them. When they describe research, they acknowledge who was
behind it ("In 2014, Replicant developers have found..."). It isn't until the
fourth paragraph, after they are certain that the reader has been adequately
informed, that they begin to actually try to advertise the product. In doing
so they credit Replicant for all features for which they are responsible,
rather than implying that these features are unique to Technoethical's
products. After that, they let the specifications speak for themselves so
that the reader can decide for themselves whether the product is what they
want.
Companies like Technoethical, Minifree, and ThinkPenguin are of course
businesses that want you to buy from them, but they consistently prioritize
accurately informing potential customers. Purism does the opposite. they
prioritize creating as positive an image of themselves and their products as
possible, and only disclose information to the contrary when they absolutely
have to, and in as little detail as possible.