They weren't forced to start with LGPL code. They did because they were comfortable working under the GPL. They did it because the alternative - writing an HTM

They weren't forced to start with LGPL code. They did because they were comfortable working under the GPL. They did it because the alternative - writing an HTML rendering engine from scratch - was not an economical option for them at that time. On the whole though, I agree with your point that no other company has released and actively maintained an open source project that is directly benefitting it's competitors. Though I would tend to believe that's more of an accident of history than any sort of belief in the open source movement.