There’s a big difference between taking a parent’s advice and giving them veto power over whether or not Boy X can date Girl Y. The OP is talking about the latter — the shadchan deals directly with the parents and if they don’t approve, the date never happens.
I think that when a single is over 25*, the parents shouldn’t have veto power over whether or not they can date and whom they can date. As others have pointed out, if they aren’t mature enough to make that simple decision for themselves, then they aren’t ready for marriage (and I wonder if they ever will be).
Nonetheless, there is certainly value in consulting one’s parents for their advice and input along the way. I’m over forty and a parent myself, and I still consult my parents for advice on life issues — I highly value their advice and respect their life experience — but they don’t have veto power over my life decisions. I think the same approach should be approached by singles as well: consult with your parents, talk with them, solicit (and value) their advice and their input — but at the end of the day, the decision on whether or not to continue with the dating process and to proceed to marriage is yours and yours alone. Parents *should not* have veto power over that sort of decision.
No one is saying (absent extreme circumstances) that parents should be completely out of the loop — but they shouldn’t have the power over older singles that the OP claims they have.
The Wolf
* Personally, I think even 25 is too high for this — but that’s another argument for another day.