Socialism and philosophy

In my reading about socialist thinkers past and present, I keep coming across mention of abstract philosophical ideas that seem not to have anything to do with socialism. For example, there's Marx and Lenin talking about 'dialectic', and I'm just now reading an article which is apparently about Badiou and modern adaptations of Maoism but goes into a whole bunch of ontological ideas on the way.
What is the necessity of such philosophical speculation, and what relevance does it have to revolutionary socialists? I've managed to grasp a big chunk of socialist theory without it.

Dialectical materialism is essentially a heuristic for identifying contradictions and formulating hypotheses based upon them—Marx's theory of class struggle being the most notable. Like anything else, it can be extraordinarily helpful or misapplied and therefore useless.

With respect to Alain Badiou and other such philosophers, they're little more than fashionable obscurantists. You can waste days attempting to decipher meaning from their work only to discover their allegedly profound insight is something as trite as 'communism must be a struggle to expand the commons.' In The Road to Wigan Pier, George Orwell complained that one of the main reasons many people distance themselves from socialism is because they're repelled by the turgid language many socialist intellectuals are fond of using, and I fully agree with his criticism. I'm obviously not suggesting that you should refrain from reading philosophy—in my opinion, the classic socialist philosophers (Marx, Proudhon, Bakunin, Kropotkin, Lenin, etc.) are the most insightful—but I feel possessing a thorough understanding of socialist economics is more valuable at this point. The philosophical justifications for socialism are really quite simple to grasp and needn't be over-analyzed.

If, however, you're really interested in reading unambiguous, analytical, contemporary socialist philosophy, consider looking into G. A. Cohen's work. He's definitely one of the most erudite thinkers I've read. (I have a few clips from a talk he gave in our Educational Videos thread, if you're interested.)