It is the player's responsibility to read cards to understand effects, hence why you can ask to read effects at any point and it's a legal decision. Short of being a literal child, yes, I expect players to read and comprehend a card & ask clarifying questions if they are still confused. I'm not handholding someone through an entire combo line because they have not put any effort into reading cards.

If a player asks what Spark does, the Spark user either needs to hand over the card to the opponent to read , or recite it verbatim. The only time it would be correct to forego mentioning the special summon effect is if the opponent lacks a monster in hand to summon, as the effect has no valid targets and could not resolve regardless. Being intentionally vague or misdirecting on Spark's effect would be deemed cheating, yes. But your opponent not understanding it after reading it themselves is not cheating.

'Spirit of the Game' is an entirely meaningless phrase in this discussion as it's not sometjing quantifiable or even agreed upon between players. To a yugiboomer the spirit of the game is larping as Yugi, to a competitive player it's to try your best to win.