I hate 'arguing' this way, but no it is not.
Straw man:
Presenting someone who defends a position poorly as the defender, refute that person's arguments, and pretend that every upholder of that position, and thus the position itself, has been defeated.
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.
For mnemonicsloth to make a strawman argument, he'd first have said something like "some people say <poor argument for $x>" and then go on "however, <picks apart argument>, so we know $x is false". Therein lies the fallacy -- a disproof of a proof of $x is not a disproof of $x.
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").
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.