Do you have more concrete examples of "pattern oriented solutions" that exist in Java and not in C#? Are you trying to say that C# is so expressive that it doesn't need, for instance, factories?
Meh, I will guess that is the usual suspects: like XML libraries, anything JEE, ORM, ... Those are the things for which Java provide an API (sometimes a default implementation) and you chose your implementation between competing ones.
The result is a mess of factories of generator of creator. Also, over the years best practice have evolved, meaning you get a variety of such mechanism in the JDK itself. With a single vendor, DotNet avoid a lot of that shit.
Then there is a huge variety of OSS libraries that integrate with each other. So you get another layer of pattern on top of the JDK. OSS libraries are extremely popular in java, much more than in the DotNet world, so that contribute to the sentiment.
Another usual suspect is a fashionable "Spring hate" or "Hibernate hate", ... Dependency injection, ORM and other patterns became mainstream on java and are very often used.
Even less hated "pattern" like mocking and unit testing started there too. A lot of projects still use older style less modern implementation of those.
EDIT: Also a lot of libraries are mature and implement the entirety of the specification they provide support for. Since java is mainly used for enterprise application, the most google-able libraries to solve problem X is generally the enterprisy one. For example if you search how to serialise to and from XML, you end up with Jaxb as the preferred solutions. You will not hear as much about XStream which is a more limited but much more straightforward approach.
I was clear enough in my opinion. I don't think it's an issue related to the programming language but how the community works. As ern said there are people in the .NET following this approach with stuff like the entity framework.
