You're right but I think what they meant is essentially a facet of Dunning-Kreuger.
Most people know enough to know that what they know is a fraction of the surface area of a subject.
But some people know a fraction of it and think they have godly expertise because they can't see the breadth and depth of the field. This is often because they can't even comprehend the complexity as they simply haven't encountered it before.
Mine is soil. I've got a graduate degree in soil science.
The most popular opinion that is wrong is all of the common ones. Soil science takes 5 science disciplines ( bio, physics, Chem, plant nutrition, and soil development) and rolls them all into one.
Not all tillage is bad
Not all amendments are good or work
There is just such a big gap in common knowledge when it comes to this topic and a lot of 'experts'
Get on Reddit and comment that something other than AMD, Corsair or any other heavily shilled brand makes a better preforming product and you can experience this first-hand.
This is weirdly specific, but I've sadly been in more than one internet "discussion" where a CNC laser cutter is shown in a video, and some knob end pops up in the comments and says "ThAt'S a PlAsMa CuTtEr NoT a LaSer sToOpId".
For about ten years I set up, operated, programmed, maintained, and repaired both plate and tube lasers made by NTC, Mitsubishi, Amada, Trumpf, Han Kwang, Mazak, and BLM. I know enough about industrial lasers to make them boring. I can tell if a shop has a laser just by driving by. A plasma cutter works different, sounds different, and cuts different than a laser, and even someone who knows nothing about either process can see there is a difference.
I just assume I don't know anything, and I'm saying what I know, trying to convey my method of thinking about problem. It's mostly for me to check if other side can communicate, and we can exchange useful information