[tannk11001]

You're absolutely right. It's casual and doesn't carry an explicit gender connotation to most people that use it.

At the same time, bringing attention to the implicit sexism (a la 'mankind') is valid. It doesn't mean anybody has to shame themselves for saying 'guys', it just suggests that they might want to consider other word choices in delicate situations or when they've got the reserves to be a little more conscientious.

[rsuelzer]

Yeah, and it if you are working in a region that doesn't use "you guys" as a gender neutral "you all" you should be aware that it can be seen a loaded term and adjust accordingly to make sure that you properly convey your true intent and not make others feel marginalized.