Learn Dutch: Zij zijn overal tegen, ook tegen deze wet. - They are against everything, also against this law.

In Dutch, you usually can't say tegen alles (against everything) when talking about things. Instead, you create a "pronominal adverb" — a special grammatical combination where "everything" becomes overal (literally "everywhere"), and the preposition swaps places to come after it. So, "against everything" becomes overal tegen.

Why does the preposition tegen come after overal but before deze wet?

This sentence perfectly shows the difference between the special adverb rule and a normal preposition! With words like overal (everything), ergens (something), or nergens (nothing), the preposition moves to the end: overal tegen. But when you have a standard noun phrase like deze wet (this law), the preposition stays exactly where you expect it, right before the noun: tegen deze wet.

Does overal tegen also mean they are "against everyone"?

No, this special combination rule is only used for things and concepts. If you wanted to say they are against every person, you wouldn't use overal. You would use normal word order: tegen iedereen (against everyone). Overal tegen specifically means "against everything."

Quick refresher: why is it deze wet instead of dit wet?