Paul is speaking to the same group - the brethren. The brethren are men who are believers. No unbeliever is ever in Scriptures called a brethren.
The brethren could not be spoken to as spiritual, but as men of the flesh who were infants in Christ. He gave them milk as infants not yet weaned and not solid food which they could not digest (understand), and the same condition continued even to the time of his writing the letter.
How unfortunate it is that you cling to that which is inaccurate, for it forces you into that very statement in which you would attribute to others.
"Just another "taint so" post, denying the obvious. If I ate "the things" of the buffet counter, did I eat some of them, or all the food? Some of the things. To restate the obvious, your bogus doctrine rests on claiming an ambiguous verse means something contextually untenable." (quoted Van post # 127)
Van, taking your statement with modification, the fallen people cannot understand the spiritual milk things of the Spirit. Paul states makes that clear.
You don't like that statement, because it doesn't fit your view. But that does not make the statement need your manipulation in which when left without does not give your view validity.
Your's is the "bogus doctrine that rests on claiming an ambiguous verse means something contextually untenable."
You of course will deny such, for that is the hold error shackles one.