When you invest, you vote with your money, helping the recipient of your monetary energy grow stronger, to do what it does now better and bigger in future. Even if you only care about returns, that's still what you're doing.
Investing in fiat-only companies and products unrelated to Bitcoin doesn't do anything to help Bitcoin, and probably actively militates against it in some way, or at the very least, is disinterested in changing the status quo of money (the mechanism by which the insane inequality is perpetuated):
If a hard money, techno-deflationary low time preference society is the only hope humanity has of surviving with civilization intact, every bit of excess monetary energy one has beyond one's basic Maslow-defined needs is wasted if not contributed to Bitcoin. This of course includes every shitcoin, most especially the dominant one Ethereum, who's biggest draw is that it may overtake Bitcoin and return the type of gains its many proponents missed out on when they dismissed Bitcoin in the past.
Of course, there are plenty of "moral" investments outside of Bitcoin. But are any of them as potent as Bitcoin in changing the fiat monetary system from a war-loving, anti-human ecocidal system of oligarchic enrichment and control to one of international fairness and peace? Of course one should help those they can in the present (not that we do this consistently), but if one really wants to change the structural inequity that's resulted in those same misfortunes, and will continue to do so, shouldn't one go with the investment that will actually make a difference in the long term? What's the point of having a "diversified" portfolio, when you're just diversifying away from a livable future?