One would presume that the founder is investing their money into something, probably equities, that is an investment in industry. They could be either selling those equities for a loan here or taking a loan against those equities to loan to GoPro (if the cost of capital is lower for them than GoPro, which seems plausible.)
I generally agree with your point about value extraction vs. re-investment.
Equities aren't investment in industry except when there's an IPO or SPO. The rest of the time, it's zero-sum.
What you just said makes no sense. How can equities come into existence except via an IPO or similar mechanism?
Equities are literally investments in business. Equity is a line in the balance sheet for every corporation.