Micro-USB is a variant of the USB-B connector. The whole point of A and B was that A ports were used on the "host" system, and B were used on the peripheral. If you remember USB On-the-Go, that was an attempt to reverse the trend and allow a USB-B device (including micro ports) to act as a host.
USB-C erased that distinction in favor of a full duplex network connection between two hosts.
USB-OTG ports are technically mini-AB and micro-AB ports that can fit both A and B plugs.
And USB-C is neither full-duplex (at least not for USB 2) nor host-to-host; there is a protocol negotiation and some devices can never act as hosts, although some can indeed assume both host and device roles.
Even in a “host-to-host connection”, only one side will act as the host.
In the same sense that A and B are variants of each other, sure.
Even though it's called micro-B, the design is closer to A, and micro supports both ends with basically the same plug. I would never refer to it as just "B". "B" means the square plug.
If we're being pedantic, it's USB Micro-B - more specifically the High-Speed variant. There's also USB Micro-A and USB Micro-AB, and all three have SuperSpeed variants which are twice the size.
I wasn't being pedantic though. USB-B is in my experience used to refer to the square plug (commonly found in printers). Micro-USB seemed like a closer approximation to what I though that poster was referring to.