most informed people don't want to discuss meta keywords anymore. it has been many, many years since they provided any significant benefit. unfortunately there is a constant stream of new webmasters that read a blog post that was written 10 years ago and refuse to accept that the magical trick of meta keywords is basically useless today.
imho meta keywords do have some small & unqiue uses but in my experience 99% of the time its a waste of time. almost always there are much better things a webmaster can do that will give a much bigger boost to rankings & usability.