Yes that is the situation in the past though. I think things are changing and the awareness is increasing now with trading forex here unlike few years ago.
Anyways, in relation to what OP asked, I think both crypto and forex are risky and having same trading pattern but one thing that is challenging in forex trading is manipulation that looks more than what you observe in crypto. This manipulation is frustrating and most times comes through fundamental which is news feed that can suddenly change the trend and direction of the market. But if you are trading decentralised coins, you will hardly feel manipulation.
What do you mean by decentralised coin in your last paragraph? A coin is a coin everywhere no matter the exchange it is traded, whether centralised or decentralised it does not matter. All of them also get manipulated by whales. Crypto manipulation is worse than forex manipulation because in crypto a single person with large quantity of a coin can influence price by dumping it but that is not how it works in forex trading. You will need a big institution to be able to move the market with their orders in forex trading.
I will like to agree with your quoted post and also yours that aside the fact that both trades are similar in the sense that they use same strategies, the manipulative aspect of both are dependent on which pair you’re trading on, forex has large liquidity or is a large liquidity market with a big market size but it’s manipulation mostly comes in from fundamentals like news, it is easily affected by news like CPI and the rest, whereas the crypto Market which has more advantages like no time frame for market closures and has far more multiple pairs to trade in also has its manipulation when trading with low market cap coins but you see those big market caps like bitcoin it is not easily manipulated because the amount needed to move it is not small but of recent the investors are also been lured by economical news too which to me makes them not too far from each other.
In terms of decentralization I think bitcoin trading wouldn’t be compare to forex trading most especially currency pairs, we saw this year how the increase in Japanese interest rate immediately affected their currency pairs and that of others too, such centralized control aren’t in bitcoin