So why would anyone think trigger = consume?
If it is working as intended then the description needs changing
As to the why, iirc (and after checking a bit) the talent descriptions are pretty consistent at using "marking/marks/mark (a/the) target(s)" when it means putting the debuff on someone. It's also consistent about when a talent consumes a mark. Reading comprehension being what it is, that makes you think "triggering a mark" is something different, in this case activating when something else
consumes a mark. If still confused, it takes about two uses of the talents in question to figure out what the behavior is, heh. The more you know and all that, ehehe.
It... seemed pretty obvious the first time I read the talent, m'self, and glancing over the talents again still makes it look really clear what was intended. Still, if folks are getting confused clarification can't hurt, too much. Might be a bit more subtle as-is than second language folks are used to, or somethin' along those lines.