In re "parents that feel uneasy", I think in a decent amount of cases at least this may root from places outside ignorance, depending on what you mean. There are some views that would be a bit more fair to consider on the ignorance-rooted side (homophobic and transphobic concerns as an example).
Although if we look at some others, it's more a literal disagreement, hard to claim its rooted from ignorance. Like one thing we run into issues with here in the US is how heavy our religious past is, a lot of sex ed programs still take an abstinence-only view. Although, it's hard to say that roots from ignorance, because it's an opinion based on a want, in some cases they're not really projecting a factual measure besides it can be the "best" way to avoid pregnancies, STIs, etc (which is kind of true for pregnancies)
There's also some weirder worries that are slightly legitimate but I don't think EU nations would have to deal with. Our states here have a lot of power, and one thing that comes with that, is setting age limits for certain things. An actual wise sexual education program would delve into things like age of consent, etc, although that could make really confusing education programs here since you could cross state lines and be dictated by an entirely different set of laws in that regard. This could incidentally lead to that education presenting a belief that could lead to legal issues, and given how our schools work in general its a bit unfeasible to touch on every states law in that regard.
Statistically we tend to top out most of the globe with some of those issues in terms of quantity although, fair debate surrounding that since other countries with closer population numbers aren't as forthcoming about their statistics. Over here, some of the worries here come from both due to the coercive consent behind some cases, that can be promoted by having that knowledge (at any age). It also lends a bit heavier to those worries though, than it might elsewhere.