I've seen the result of intellectual property theft and I don't like it. The market adjusts and less people spend time creating things that are easy to copy, so the quality of those things are diminished.
Can you demonstrate there would be a net loss for society? The burden of proof is on you.
Who even remotely cares? It is not a matter of net loss for whatever people you are willing to lump in some group and call them representative of society, it is a matter of loss to you, as a consumer, for certain quality products are not profitable enough because they are too easy to copy and as such only low quality of such product is ever only made (read low investment).
This started as a fundamental look at property, let's keep it as such.
Also ethics and morals are not relevant in this discussion, because your morals are yours only and you cannot implement them into anyone. What you can expect though, is consequences for you actions, i.e., you do not respect my property by stealing the design I've come up with, do not expect me to respect your property, however material or immaterial it is.