But you can't say "no". All you can do is ignore the quest you were already given. Thus the game assuming you are going to complete it.
Yes, you can, they appear more often than not really. Yes, the quest still appears in the journal but I really don't get why that's such a big problem because it always worked that way.
It is. The quests are not only banol, but they're blatant attempts to guide the player in certain directions. This minimizes discovery and serves to undermine true player agency. They aren't undertaken because the player, through their own agency, sought them out, but because the game is constantly reminding you of all the content you have yet to complete.
If the game is designed in such a way as to compel exploration and discovery because the world is, in and of itself, interesting and worth the examination, then one need not use transparent contrivance to goad the player into participating. This is why Skyrim's stories so often fall flat. There is little incentive for completion beyond completion itself. Quests offer few choices, fewer consequences, and most fail even to provide compelling linear narratives.
These "transparent contrivances" are a way to compel exploration. The player won't just go and explore by themselves, they kinda need a guide for that, a path to start off with. These quests provide just that.
This is a similar thing than the quest arrows, both of them are complained about because they ruin exploration. How, in both cases you know the destination, but that's about it, if your goal is in another city entirely you still have to walk there, you still have to find the way, you still have to get there.
And it was mentioned before, you are not forced to continue with this quest.
They haven't missed a quest because they had no compelling reason to explore, could it be because they couldn't find it? You say this like Skyrim is missing in content, which is completely untrue.
In other words: EXPLORATION DOESN'T WORK THAT WAY!