[james_in_the_uk]

Not excusing shoddy lawyering but here are some thoughts:

1.Many of these lawyers probably don't actually specialise in open source. Especially if they work for companies as project or product lawyers. They've probably been allocated it as part of their remit, along with issues like contract and data privacy.

2. Open source is a niche within a niche (IP law). It requires a nuanced understanding of copyright and patent law but also requires strong understanding of software development practices. Concepts like GPL linking are really tricky to grok even if you are a knowledgeable IP lawyer.

3. Several popular open source licenses weren't written by lawyers and so can be a little ambiguous when read against the relevant jurisprudence. Most are not well tested in court and so it's hard to give definitive advice on how they work.