Agent preferences are a great way to find your perfect agent, but they aren't the final word.
This can be a great way to get a bit more insight into what agents want to see, but it can also be dangerous. #MSWL and preferences aren't the final word. Agents are just like readers. We have our favorites but that doesn't mean something new can't surprise us.
For example, I state in my preferences that contemporary isn't my favorite, but I'd never say not to send it to me. I never know when something is going to surprise me and be exactly what I didn't know I was looking for. Unless an agent specifically states there is a genre or subject they don't want to see, it doesn't hurt to query them.
That said, do keep in mind that you are looking for a business partner. If an agent currently only represents adult romance, it's unlikely they have the connections to the right editors to sell your MG space opera.
Another thing to keep in mind with preferences and wish lists is that agents aren't sending in an order for manuscripts. I'll often hear authors lament that although an agent said they were looking for a YA urban fantasy about monkeys from space, they got a rejection on their space monkey manuscript. Their conclusion being the agent lied.
Remember that there is so much more to a manuscript than it's genre and premise. Things like tone, narrator, voice, pacing and a laundry list of other aspects go into each novel. Way too many descriptions for an agent to put into a bio paragraph or tweet.
So what does this mean for writers still in the query trenches? Don't ignore wish lists as they can be a great way to find agents who might not have normally popped up in your search. But don't rely on matching up with an agents preferences as an automatic in. At the end of the day every agent and editor is looking for the same thing: a fantastic manuscript readers can fall in love with.