You could contact Flexport, and let them know that someone is spamming the HN boards with random "hiring" post that point to news articles about Flexport.
If you politely point out that it looks like another company is trying to sabotage their hiring by giving them a bad reputation, I would bet that someone would take notice.
If they are a legitimate company, that is... It is always possible that they don't give a damn about their reputation because the company does not actually care about their tech hires. In which case, anyone who isn't desperate and has a little sense would know to stay away from Flexport at all costs.