well, ha ha, very funny. please stop.
Let's keep vbot to on-topic things, and use our own accounts for 'jokes'
1) When someone explains that it's "for a joke" it obviously sounds dumb and not funny, but people like it. Source: Am a people.
2) What on-topic things are there, though? Yes, sometimes we want to link to an important thread, and to give some topical warnings, but those are hardly constant things. Gamedays are announced with event notifications, so what's the point? I can't see much of a reason to be so strict about this in situations where you really have to scrape the bottom of the barrel to find anything "on-topic" to put in the MOTD. If you take a moment to read the general climate of the chat, there's no illusion of professionalism there. Nobody gets disrupted by dog pics, nor do we have any absolute need to trust the MOTD to be the sole carrier of the utmost important messages.
What I'm trying to say is, if you happen to dislike this, that sounds like your problem. It's not the least bit problematic in any practical sense of the word, and if you wish to not see the more humorous MOTD posts you need only look away.
Edit: Rewording.