would summoning a lemure qualify you for tainted sorcerer?

[gogogome]

As has been noted elsewhere in the thread one of the definitions of "Instruction" is "Teaching; Education". It's not the author that's failing at grammar, it's people willfully ignoring context clues that are telling you which definition of instruction to use, again also noted earlier in the thread, the fact that the first part of the special requirement is that you be taught by an existing tainted sorcerer. When you put 2 and 2 together, the definition of instruction that you're meant to use is crystal clear, and anyone claiming otherwise is squinting way too hard to justify a cheesy entry method.

First, how is this "cheesy" when the entry requirement is simply saying your wizard teacher was a tainted sorcerer?

Second, you are the one squinting real hard and not reading the sentence properly.

Upon summoning a demon or devil you gain instruction. This is clear cut. This is how the English language works.
It does not say you must receive instruction. It says you gain it. Summoning a devil gives you instruction.
The text does not say "must have summoned a demon or devil and received instruction" which is required for your interpretation to work.

Post #18 fully explains what "to gain" means. It is not interchangeable with "received".

In one of those examples
"you must have summoned a devil and received respect." means something very different than "you must have summoned a devil to gain respect."
The first example has a 2nd additional prerequisite. The second example does not. It only has one prerequisite: summoning of the devil. If this is still confusing to you then I cannot help you without going into a lecture about grammar, which I am not willing to do at this time.