Yes it is probably a thing in their configuration framework, where any change to an item will send it a message to update its state, even when the change has no effect on the state at all.
Of course it is difficult for us to see what changes exactly affect the state. One would think a comment certainly doesn't, but what about a name, for example. An item name in many cases probably is as insignificant for state as a comment, as it is just kept alongside the lower-level name or ID used by the system. In other cases, maybe not.
Likely it is quite tricky to compile a table of changes that can be safely made without bringing the item down and back up, and MikroTik chose not to worry about it and just do it every time.
We can only hope that this is something that will be improved in v7.
On the other hand: relax. Competitor's products do an entire REBOOT almost every time you make a minor change...