I would say it's not. There's many advantages to hiring remote workers, they've been discussed at length elsewhere. One advantage is not having to pay office space, which indeed lowers cost. However DO has a nice office in Manhattan so really... they're not saving much money. And then on the term of compensation, for some reason DO pays it's remote employees really well. I don't know how this changed in recent years but people in NA and EU are all paid handsomely despite being remote. I don't know about other locales.
The reality is that top talent, even if remote, is competitive whether they are in NYC/SFO/SEA or not. And DO has some pretty talented people on staff.
And then, having people in all timezones is definitely an advantage for 24/7 support. I'd say it's not negligible, and not an after thought.
Now about english fluency, it's only that important to english native locations. And really, most of tech does not necessarily have english as a first language - I certainly don't. So I'd say that encountering support engineers with imperfect english shouldn't be a problem to anyone, and definitely not a sign of cheap labor. In fact, I'd say bitching about someone's english proficiency in tech is kind of counterproductive and I find it discriminatory.
Anyways. DO doesn't hire international employees to get cheap labor, that's a preposterous proposition. And with datacenters around the world and a large presence and customer base, it makes sense to have staff on board from many of these areas. And that staff might answer your tickets at night when they're on shift. Shouldn't they?