Agnosticism is attacked from both directions, and the attacks are the quickest route into what it does and does not claim.
Believers argue that suspension is not the neutral resting place it presents itself as. William James put the case in The Will to Believe (1896): where an option is genuine, forced and momentous, refusing to decide is itself a decision, taken under exactly the same uncertainty as either alternative, and it forecloses whatever the believing life might have shown. Pascal's wager is the older and cruder version of the same complaint. Both hold that in practice one lives as though one had answered, whatever one says.
Atheists argue the opposite way. Dawkins's seven-point spectrum in The God Delusion is the standard modern statement: he places himself at six rather than seven, technically an agnostic, while insisting the working position is atheism, because nobody suspends judgement in this way about other unfalsifiable claims. The sharper form of the complaint is sociological rather than philosophical, that agnostic has become, in much ordinary use, a way of avoiding the social cost attached to the word atheist rather than a distinct epistemic position. That charge is contested, and agnostics reject it.
The agnostic reply is that both criticisms assume the question behaves like other questions. If the strong form is right and no evidence could bear on the matter, then confident denial is as unwarranted as confident assertion, and treating the two as asymmetrical begs precisely what is at issue.
There is a separate difficulty for anyone reading numbers. In modern surveys agnostic frequently records something closer to unsure, undecided or has not thought about it than the considered epistemology Huxley meant by it. The label and the position it named have drifted apart, and the drift makes survey shares a poor proxy for how many people actually hold the philosophical view.