grammaticality - “is like” , “are like” comparison between singular and plural

So I had a debate with a friend, where that friend is of the opinion that you can't compare singular entities with plural ones

Eg : Women are like a magnet, always attractive! (Just an example)
Women - Plural
A magnet - Singular

is wrong according to my friend.

Whereas, I think the above is right. The only thing that should matter grammatically is, using "is like" or "are like" based on which is used first, Singular or Plural.

Eg: The above sentence if Singular entity is used first should be -

"A magnet is like women, always attractive!"

Am I right in the above two sentences?
I'm also looking for sources which can validate this usage. Thanks.