Well I've been doing (what I think of as) Hobbyist Engineering for about 20 years now and I still don't consider myself an "Expert" . There are clearly people here who are though, probably because they do/did some form of engineering for a living, whereas I never did.
What I do have is quite a bit of 'experience' and a fair range of machine tools collected (accumulated?) over a long time. Nearly all of it is pretty old, well past it's prime and none of it cost too much. So if I see a question that is in an area where I have some of that experience, then I will generally chip in. Normally this is in relation to the machinery I have or the type/size of models that I make. But I also think herein lies the problem.
Everyone has different expectations (quality, budget, time) and levels of experience within their own spheres of interest. If you build 7.25" locomotives (or restore cars, repair clocks etc.) then your expectations and experiences will be very different from mine ( I build in Gauge 3). As I've mentioned, my machine tools are pretty old and need, shall we say, a high level of sympathy but I've learned to live within their limits. In this respect, I can probably claim more 'experience' than those with newer/better machinery when the question specifically involves some kind of older machinery & their related problems.
My tooling of course also effects how I approach my modelling and I prefer many "obsolete" work methods (to some newer ones) either because they suit my machine capabilities or sometimes simply because they are more affordable (e.g. cheap!). I accept that they might not always be the absolute best/most modern way but the key thing here is that they meet my particular needs and equipment.
I will admit that I do occasionally get a bit peeved when people are dismissive of these methods and/or older machines, probably because their actual experience lies elsewhere in different or newer types of machinery, larger or much smaller sizes of work or perhaps industrial practice. It may well be that they are perfectly correct, that their way is the best/fastest/most efficient and I'm certainly interested in hearing about these alternatives. But there may be good reasons that I can't (or won't) use them and it might well be that others here share my needs in this respect..
So whilst there are clearly some here who really are "experts" within their own fields, they may not have as much 'experience' in some things as others (who are undoubtedly less expert). I feel this is often where any conflict/confusion in the advice being offered arises.
There's no particular solution to this issue, although once in the (distant) past when I saw something that I thought was particularly misleading, I will admit I contacted the OP directly and told him so (and explained why). Generally though, most of the advice given here is very well intentioned and (I'm sure) also generally helpful to the OP.
Regards,
IanT