First of all as an investor you ought to be focused and concentrate on your thing instead of looking at what others are doing but if you must look at what others are doing or saying even if they are not..., don't be drive by those things rather learn to be contented with what you have ( your capacity), if there is something great or interesting they are doing and you feel it can help you if you apply it your investment and you have what is required to carry out this then you can go ahead there is nothing wrong in doing this but don't allow other people's success or things to control you, be confident in yourself and know you must not be like others.
To be more specific, "all hands are not equal". Meaning we all at different financial level, so we shouldn't look at other investors and do whatever they do. Most of them can choose to risk an amount knowing full well they have suitable businesses and back up funds elsewhere to fill in the gap. It will be like they never lost anything. While there are some investors that will be affected drastically. At least I have come to realize that working at your pace and accumulating consistently is all that matters. You can keep investing while growing your income, it doesn't stops that.
You're right with the saying that all hands are not equal but I doubt your following descriptions. Bitcoin investment is more personal and should be done within everyone's financial capacity. This is because if you must invest and hold successfully, you must not overdo it. Any fractions of bitcoin you acquire beyond your capacity can ruin your entire bitcoin stash and this is why we need to be careful about how much and how often we invest. A good investor analyses his income, takes care of all his basic responsibilities which could affect his ability to succeed. When you have a good Cashflow management, then you would understand that it's not all about investing, it's more about HODLing for a minimum of 4 to 10 years in order to be more certain about possible gains.
About investing what you can risk, the context of your description makes it appear like you are referring to bitcoin gamblers. This thread is for buying to HODL and advocating for a more financially friendly investment is to help you to successfully hodl your bitcoin stash for a long time without panic selling or selling at loss due to unforeseen circumstances. It shouldn't be misleading, bitcoin is an asset that is worth investing into with consciousness to ensure it's holding success.