Learn Portuguese (Portugal): Eles atualizaram a proteção para me proteger os dados. - They updated the protection to protect the data for me.

Because of the preposition para. Usually, a verb in the infinitive takes the pronoun at the end (like proteger-me). However, certain prepositions—specifically para, por, sem, and até—act as "magnets" and pull the pronoun before the infinitive.

The translation says "protect the data for me", but couldn't this also mean "protect my data"?

Yes, and "protect my data" is actually the more natural way to think about it! Portuguese frequently uses an indirect object pronoun (like me) combined with the definite article (os) to indicate possession. This structure is very common for things intrinsically linked to you, like body parts, clothing, or even personal files, instead of using the direct possessive os meus dados.

Why is the preposition para used here instead of por?

When followed by an infinitive, para expresses purpose or intention (meaning "in order to protect"). If you used por here (por me proteger), it would change the meaning to express cause or reason, translating to "because of protecting my data".

Since the subject "they" is doing both actions, could the sentence use the personal infinitive protegerem?