[asteroidbelt]

> Sarah, Ben

Alexa is easy to recognize by software with very low error rate unlike Sarah or Ben.

> Of all things I am suspicious of why they would choose a female name for an assistant.

For the same reason airport announcements are usually voiced by women. For the same reason satnav is voiced by women. For the same reason language learning tapes are voiced by women. People (both men and women) are more comfortable listening to women.

I suspect you suspect it is because of assistant being women stereotype, not it's not that, and no need to look for social injustice everywhere.