Should I use plural form of socializing in this case?

Dear All,

Recently I was editing a proposal and came across this writing. It sort of makes me confused that a plural form of meeting is used in the sentence starting with Socializing. I talked to a professor who thought meeting is a noun so it's in plural form. But I thought the word "and" is an equal conjunction and is used with a consistent format. In this case, a gerund form is a better choice. If

If meeting is a noun, socializing can also be found with a plural form. Also on some webpage http://socializingnewcastlecomau.melbourneitwebsites.com/cat/index.cgi/shopfront/view_product_details?category_id=12659&product_id=396487, it's also in plural form.

Could any one who knows the answer explain it? Thank you for your time and effort.

The purpose of the class is to let students practice the types of English structures that are commonly used in workplace settings. The five key areas that will be covered are: Socializing, Telephoning, Meetings, Making Business Presentations, and Negotiating. No special knowledge of business terms or concepts is required.

Best,

Art Wang from Taipei, Taiwan