Your use of 'strawman' is incorrect.
He was presenting me as someone who had no experience with a startup, thus shooting down my arguments about the ease of starting up. Explain how this is incorrect? He presents me as an individual with no experience with startups. He then uses that to attempt to shoot down my arguments.
In other words, it's not about presenting a person as a poor defender, it's about presenting a poor defense. Cutting straight to a person's worth as a commentator -- as mnemonicsloth did -- is argument "ad hominem" ("to the person").