With listining to YC president's 10k Etherum video in 2021 I lost money

He since then made the video unlisted. How can I believe what they say about any other thing? when they just unlist things after promiting them?

https://twitter.com/garrytan/status/1402648829732614146?lang=en

https://www.youtube.com/watch?v=jo58qEoThSs

is this all the public invesment opportunity they can share? so we lose money afterwards?