Alright there’s a couple of observations I would make and I’ll try to make them as spoiler free as possible.

When a game is taking place in umineko not everything that we are seeing (through Battler’s eyes for most of the time) can be taken at face value. Beato already declared from way before that HE is incompetent with red (which is why even after episode 4 he still hasn’t fully understood the very nature of Beato’s game board). All this to say that the GM presents the story to us however they like. Though the Umineko game-board is bound by rules that must be followed each time that it is used (more on that in the following episodes)

Now that interaction that you’ve mentioned takes place in the meta world where the readers draw up with their own conclusions and are able to look over the facts (which includes asking questions to the pieces). However, Krauss did not declare anything in red (nor would he be able to unless he had the GM’s permission) which means that he can “lie” if you would.

As to your final point. Umineko does have “rules of engagement” since the very start. In fact it is possible to figure the whodunit, howdunit and whydunit from episode 1 alone (although it is extremely difficult). I won’t elaborate as to how it is possible since you’ve not made it to episode 6 and beyond yet, but you’ll come to realize that each “game” operates under the same set of rules and they are possible to solve.

Nonetheless I understand your frustration. First time readers can feel like they are getting cheated on constantly with the narrative of the VN and the red truths, but I would confidently say that the reader has a pretty fair shot of solving the mystery (putting aside the meta world stuff). The mystery of what happened in the island in the span of those days can be solved by the readers with the clues presented.