Solution:
Electrical plugs. Sorry, I don't know enough about others to contribute anything additional.
Explanation as requested:
Explanation as requested:
"There are many different types of men;"
"Men" referring to the "male" pins of an electrical plug.
"They often come in groups of two or three."
Most plugs have two or three pins (usually a "hot" and "neutral", and sometimes a separate ground pin).
"Each group has a matching group of women,"
"Women" referring to the "female" parts of the receptacle.
"But they should stay with their compatriots."
Keep plugs with their intended receptacles or risk electrical damage/fire.
"In Europe we have several different kinds;"
There's no single European standard on plugs.
"The Americans are only half as good as us."
Could refer to the relatively thin plug blades in North American plugs, but more likely to the difference in voltage of household electrical service (120V vs. 230V).
"Those from Down Under are all thin and weedy,
Not as tough as the solid British men."
I'm not familiar with Australian plugs, but presumably the blades are thinner than those used in the UK (which are certainly stout).
"The French can have a woman in their group;"
Looking at plug Type E in the link above, commonly used in France, there is actually a "female" bit in the plug that accepts a pin from the receptacle.
"The Israelis won't fit into any other land;"
Type H is "used exclusively in Israel, the West Bank & the Gaza Strip." (same link)
"But if you need translation services,
I can provide you with a magic cube."
Adapters exist that allow you to plug a device into a physically-incompatible receptacle. Some of them are vaguely cube-shaped.