1) It isn't hypocritical to ask someone to articulate why they don't agree with an assertion.
2) No, that's NOT how the burden of proof works. The initial presumption is that the moving party is speaking truthfully, and objections are raised afterwards. If the objection has enough proof, then the initial party is under the burden to refute the defense. This is literally how our court systems work in civil cases.
The alternate assumption, that every element of every statement needs to be laid out for any statement to be found to be valuable means that every post here would start with a discussion of epistemology.
Edit: torstenvl's post is incorrect - in the initial stages of dispute resolution, in summary judgment and the phases where the claims are evaluated for importance (whether the originating document should be struck, etc.), the claims as drafted in a statement of claim are assumed to be true. This is why default judgment is accepted - because the pleas are accepted truthful. Pleas are also evaluated as if they are true in summary judgment and a number of other pre-trial levels. Once a defense is filed and objection is noted does the burden switch and the evidentiary examination begins. But that requires a defense, and a defense will be struck if it says nothing.
Fortunately, this procedure lines up fairly well with Bayesian inference and the principle of charity.
In any event, this meta discussion seems to have generated ill will and little understanding, so I'll let it rest where it lies.
Thanks for the spell-check! Common error of mine.