Mistakes are part of life from mistakes we learn but it's very much better if we learn from other persons mistake as you have listed,
Though literally you can't totally take away mistakes because some do come as result of thinking that what you're doing is right and at the end it end up being a mistake.
Too, making mistakes sometimes is good because mistake is part of learning and some mistakes taught you what you know today.
In General it's good we avoid mistake in our trading career as much as we can so we don't end up losing our hard earned money and mostly learn from other people's mistake.
Based from the list of the OP, I believe, most of us had experienced a thing or two from the list. Like using exchanges with high withdrawal fees. Sometimes, we can't avoid to use a specific exchange if they are the only trading platform that has trading pair for your coin. So you will end up using that exchange because you have no other option. Not all projects can accommodate to list in several exchanges. Usually, at the start, they will only list it to one exchange that they can afford to pay the fees. But of course, if you have other ways, you can always opt for much better trading platform. This is why for me, I don't consider it as a mistake because most of the time, it is your only option to take.
Yes, its true what you said and I've been in that situation too, but there is a line to read in between in this point, that is, there different between full time trading and partial trading, when making the post, the category of persons I had in mind was full time traders and not partial traders.
Partial trading is (just as you said above), when you invested in a coin in their ICO or whatever type of fundraising process they used, and are just getting the coin listed for on the first exchange, you probably would want to sell your stash, and buy back at a lower price and sell again and buy again at a Lower price and sell again, one can keep doing this for as long as he or she wants, provided he or she is making profits, This is partial trading to me.
But full time trading is trading on already established coins that are listed on almost every exchange you can come across, this usually requires the trader to do some work like, researching, technical and fundamental analysis to determine whether price is gonna go up or fall, people in this category are called full time traders, they have trading as their primary profession. This are the set of people I had in mind when I made that point of "not to trade on exchanges that take high fees.