I'm agnostic towards those who push such a strict definition of Agnosticism.
I gave a fairly strict definition of agnosticism above. It is a technical term and if any concept or is to be debated at all, a useful first step is to define what the concept is.
That is not to suggest that the other things that are also sometimes less formally described as "agnosticism" are not also valid and important positions in their own right.
Whatever labels we use, there is an important qualitative difference between, "It is fundamentally impossible to know whether God exists" (a strict definition of agnosticism) and "I do not consider it to be proven whether or not God exists" (a less strict definition in common use).
Further upthread, some people have argued that atheism is a "belief" or even a "faith" analogous to religion. I personally disagree with this.
I was recently reminded of the way that Sartre argued that "nothing" is a special sort of "thing".
"Nothing" is treated as a noun, and a noun is famously a "person, place, or thing". Sartre spent a lot of time trying to define and argue exactly what "nothing" is.
I would say that "nothing" is not a thing in its own right, but simply the absence of a thing. Similarly, "atheism" is not a religious belief, but simply the absence of a religious belief.
If my wife asks, "Is there someone at the door?" I may look and say, "There's nobody there." It does not mean that
nobody is a special sort of person who is actually at the door.
"There's nobody there, darling."
"There was nobody there yesterday. I wish he'd piss off."
However, as "Nothing works faster than Anadin," whenever I have a headache, I take nothing for it...