I spotted this on twitter and was pleased to find that I understood what he was annoyed about
The headline writer has got in a mix-up between two tenses. He could have gone with the imperative “habituemo-nos” (let’s get used to wearing masks) or made a pronoun sandwich with the future tense “habituar-nos-emos” (we will get used to wearing masks) but he’s instead tried to put the pronoun in the end of the future tense and people are riled up.
Regular readers and grammar nerds might remember the terms for these positions. When the pronoun goes on the end of the verb it’s caller “ênclise” and when it goes in the middle, its called “mesóclise”. The missing third term is próclise, where the pronoun goes before the noun. The rules are set out here if you want some good, solid grammar broccoli for the day.