so the results will include every possible string of characters ever.
That’s just not true. One monkey could spend eternity pressing “a”. It does’t matter that he does it infinitely. He will never type a sentence.
If the keystrokes are random that is just as likely as any other output.
Being infinite does not guarantee every possible outcome.
That’s exactly my point. Infinity can be constrained. It can be infinite yet also limited. If we can exclude something from infinity then we have shown that an infinite set does NOT necessarily include everything.