I'm really bad at timely review, but it might make sense to rethink some
of the wording in a future version.
"unnecessarily" seems unnecessary to me here as it implies the existence
of "necessary confusion" and/or some deficiency in some new users. Also
"doubting" implies questions of belief.
Of course, this sort of "bikeshedding" over the wording can take
arbitrary amounts of time and discussion without any significant
improvement. I'm just throwing out another suggestion that might be a
bit more careful about avoiding condescension:
Some of LilyPond's design decisions are not self-evident but may
require a larger context to understand. A number of restrictions
are a consequence of the current design and/or implementation and
are both well-known and documented. For that reason, it is
recommended to work at least through the Learning Manual before
reporting issues.
All the best