Weak agnostics are simply without belief in God. They make no claim and thus have nothing to defend. Strong agnostics claim that nobody can have rational belief in, let alone knowledge of God’s existence or non-existence. That is a robust claim in need of supporting arguments.
I meet a lot of ignostics on social media (though most are not aware of the term or that it applies to them). This is the view that the concept of God is incoherent and/or hopelessly ambiguous and/or vague. In most cases, it seems to me that these folk are committing the fallacy of special pleading by raising objections to the word “god” that would apply equally to terms they regularly use without a second thought like “love”, “person” or “time.”