If a new company employee of foreign nationality introduces his/herself with their real name, and their new coworkers say, 'What the heck is that? It's so hard to remember,' then that's harassment.

A genuine human reaction of surprise to something they've never encountered before is not harassment. It might be rude, ignorant, inappropriate for work, or maybe even racist depending on how it's expressed, but it's not harassment. This is a good example of how the term is overused in Japanese discourse.

After making that genuine human reaction of surprise though, if the coworker refuses to try to learn and use the new employee's name, that would be harassment.

f a new company employee of foreign nationality introduces his/herself with their real name, and their new coworkers say, 'What the heck is that? It's so hard to remember,' then that's harassment.

Its very rude but I wouldn't call it harassment.

Certainly bad manners.

My wife was forced to go by her Japanese maiden name at her former work for three years because her boss found her (my) last name hard to pronounce (its not that hard). That is 100% harrasment.

Hard to say it is harassment or not, but it is close to it. Japanese do have problems pronouncing foreign words due to the linguistic simplicity of the Japanese language, but where I come from, to react like that to a foreign sounding name would be seen as verging on racist and could well end up as a formal complaint and disciplinary measures.