IMHO some light users should be free - niche users who don't have significant budgets or would be a support burden. Others get enormous value in 5 minutes, have easy budgets for this category of software and should be paying.
It's a little weird to suggest that just because someone wants to use the product of someone else's work only for a short time, that use "should" be free.
I think the context of “should” matters quite a bit here. For example the claim that everyone should have free access as if by right is quite different than the claim that as the producer of said software this is your best bet.
I have genuinely deployed tailscale in paying locations on basis of my really positive experience on the "Personal" plan, which is effectively almost the whole product for up to three users/100 devices, for free.
I don't think there is a universally right answer for all products/services on this question though.
I wouldn't be quick to judge either way.