Can an atheist blaspheme, if there’s no God in their universe? Just asking(no one else is staying on topic either.....well- not everyone, to avoid absolutes, that is)!
Technically, yes. Blasphemy isn't about what you believe, but what you say or do. That's why it is so dangerous to those who hold power using religion as a claim to legitimacy.
Though there are some cases where police have had to enforce religious laws only upon the faithful, but not on others.