Earlier quoted context omitted.
In many countries you can't sue for defamation as easily as you appear to be able to the US. In the UK its required that you demonstrate loss or reputational damage, given how obvious it is that this is a mistake and the speed in which it was fixed, I think its highly unlikely to stand up in court. Simply calling someone a name isn't enough. OP appears to be in Switzerland, where I'm not familiar with the laws.
You have it backwards, suing for defamation in the UK is considerably easier than in the US. The 1A in the US makes defamation and label very hard to prove - you must demonstrate that the statement is false, that the defamer knew it was false, and that you suffered damages as a result. All three must be met. In the UK malicious intent is all that is needed - even if the statement is in fact true.
I wonder if defamation laws need to be extended to cover defamation by negligence?