Suppose someone has divergent interests. Maybe they are interested in computing
and hunting. If they want to discuss things and cultivate a following in each of these communities, should they be required to tweet both from the same account?
What if there isn't a lot demographic overlap? Twitter doesn't provide any kind of tooling that would allow one to follow only the relevant tweets in a given account. This is especially relevant if the interests/communities at issue not only don't have a lot in common, but actually spend a lot of time at odds, which is the case for many interests. It'd be impossible to have some followers from such groups who wanted to hear about the one thing without simultaneously alienating them by talking about the other thing. Computing and hunting are good examples because your average cypherpunk's opinion and worldview is much different from your average hunter's opinion and worldview.
I have personally started a handful of different Twitter accounts intended to engage with different communities. None of these perform any automatic activity at all and I basically use them for a couple of days and then give up because it's too much effort (recently, more because Twitter blocks the accounts almost-immediately).
More accounts than people is absolutely not a reliable indicator that "you have robots registering" (especially when businesses etc. are expected to register). That may be a better metric if Twitter provided useful filtration tools, but even then it'd be shoddy.