I didn't know that the "Principle of Charity" was the official name. There are a bewildering array of formal fallacies many of which are the same as. or a very slight variation on, others.
The example I usually use for what seems to me to be the "Principle of Charity" is "The three-legged dog effect.":
[A is trying to demonstrate that 2+2=4]Misunderstood generality
A: "OK, imagine a dog. It has 2 legs at the front and two legs at the back. All dogs have 4 legs, therefore we can say "2+2=4."
B: "My dog's only has three legs... it had an accident.
C: "Yeh! Not all dogs have four legs - are you saying 2+2 can also be 3?"Misunderstood individual
[A is trying to demonstrate non-linear effects]
A: "If you imagine that a dog can run at 30mph, we do not expect that it will be able to run at 75% of that speed if we remove one of its legs."
B: "How do you know? Have you ever cut off a dog's leg?"
C: "I think it's possible - that's only 22½mph... OMG! Did you cut off a dog's leg? That's sick!"
B and C fail to apply the "Principle of Charity". (They are trolls or idiots.)
The "Principle of Charity" merely restates: "The general example does not include the individual example and the individual example does not represent the general, except where the general is a law or the individual is an example of the law."
This all falls under the fallacy of equivocation, in which a particular word has (or is taken as having) one meaning in one part of the argument, and a slightly different meaning in another. Equivocation is the result of a lack of critical thinking. Politicians, the religious and salesmen are famed for their equivocation. I'm sure Isaiah was no different and it would not take much to find him equivocating.
UPDATE- Bradford Tuckfield wrote: " I think this principle is much older than 60 years.
Bradford Tuckfield needs to have his head examined. Here he is commenting on the "Principle of Charity", and what does he do? The first thing he does is "equivocate" and misunderstand for his own religious purposes!
Just look at what he has said rather than what he means: He means to say, "The name "Principle of Charity" was coined 60 years ago, but people have been behaving in the way described for much longer." - Well... what a surprise. He then goes on to mention Isaiah (c. 530BC) as if the first author of the first part of Isaiah in some way revealed this truth to the world because Isaiah was a prophet of a tribal Bronze Age god - there is no evidence that he did - Isaiah could have been quoting anyone. If Tuckfield looked further back to the Chinese or Egyptians, I would be surprised if he did not find that the principle was around them.
If we put Bradford Tuckfield's comments in a more obvious form, we have "I think Australia was there before 1606 when Willem Janszoon first mentioned it. Indeed Henricus Hondius assumed that it was there."
That said, Yes: beware of the "Principle of Charity" in debate, but do understand that we have to be clear on what someone did mean... and, where there is ambiguity, only they (bit not always) may know that.