I'm not who you replied to, but no, no, I don't think that's an "opposition" to writing in the sense that it's making us stupid or replacing oral traditions.
From my limited understanding of history and Greek philosophy, Socrates valued dialogue, a "back and forth" for understanding. Basically a scientific method of probing to understand something or someone. This needs to exist to be fully sure you understand something. Sort of what we are doing now.
A static piece of literature or a speech can't be probed for more clarity. You may read something and come off with a completely different understanding from the author. You might even pervert or "abuse" the original intent since words can have multiple interpretations.
I don't think there was opposition in the sense that you shouldn't write. My understanding is just that in order to truly understand something, you need a dialogue. It allows you to actually arrive at what was meant to be conveyed.
It actually seems sort of ironic that people are saying this about Socrates because of what was written about him….