I get what they mean, when I first started reading Theory, I wanted to avoid the concept of investing completely, thinking that by participating in a capitalist system and looking for financial advice from the news to be more financially stable, I must be a Counter-Revolutionary/ Capitalist. Admittedly this isn’t how I think anymore, if you wanna invest because you already have a job and don’t wanna break your back working a second one, I see no harm in safely investing properly. Also important to remember that Engels was a factory owner, he participated in Liberal Economics and was profoundly influential to the Communist movement