I am reading this and the words of @gmaxwell
(or any other software for that matter) like it was the private key,
A bunch of these sites are "brain wallet tools" (for brain wallet fools) and they hash the data being input into them. E.g. they compute sha256(input)*G rather than input*G. If it accepts anything other than a number then it's almost certainly hashing it.
are what i dont understand, does it mean that the "brain wallet fools" sites, do wrong calculation ??
Does it mean, its better to use a, lets say, python script to calculate ??