Parent said:

  don't build microservices to start off with

and you describe:

  because the email logic was spread out everywhere and called from multiple apps

so it doesn't sound like a counterpoint to me - you didn't start off with the email service, and only split it off after it was already established across multiple entities. Plus, you added a bunch of justifications for this, i.e you could "bring a strong argument in favor of it" - so where is the strawman in your examples?