I 100% agree with not putting all your eggs in one basket. However, I find that the average C2 strategy is worse than a traditional index fund etc. If the email was saying diversify into index funds - great!
Many C2 strategies have a propensity to explode. I don’t want people I bring to C2 getting swayed by strategies that are destined to explode due to irrationally large leverage etc.
I do agree that investing in a large set of C2 strategies rather than just one does diversify and reduce the chances of a sudden loss. However, I think it increases the chances of a long slow bleed of high fees and internal blow ups.
I guess it boils down to I don’t trust the average C2 system and wouldn’t want my friend to come to the site then start subscribing to the average C2 system because “diversification is good.” Honestly the email probably is fine, but it still bothers me. 
This screenshot from another thread has some numbers to why I feel this way about the popularity board. It’s a short period that was tested but I would bet longer term tests would show a similar pattern.
