He's only saying that the investment in the miner was bad. Not the investment in BTC.
Why would a 100% ROI would be considered bad?
Do you also not understand the grammatical difference between bad, worse and worst?
I will try one more time to explain.
If you had $7000 to invest in BTC, you have 2 choices. You can invest directly at the current exchange rate or you can invest in a Jupiter for a predicted amount of BTC over a period of time. Those are your two choices. Both have the risk of the exchange rate changing. Investing in a miner has an added risk of delays/difficulty increases. You should only choose to invest in the miner if you believe it will mine more BTC than you can purchase. If your miner made less BTC than you could have purchased directly then you made the wrong choice. The fact that you still made a fiat profit is great but it was not because you decided to invest in the miner but because you decided to invest in BTC via the miner but for a worse rate than you could have gotten on an exchange.