Is it infringement to buy genuine software and lend it to others for free?

it doesn't belong! There are exhaustion doctrine principles in patent law. The principle of exhaustion of patent rights refers to that after the patented product (including the product directly obtained according to the patented method) manufactured by the patentee himself or licensed by others is legally put on the market, anyone who sells or uses the product no longer needs the permission or authorization of the patentee, and it does not constitute infringement.

after purchasing genuine software, you don't need the permission of the patentee to use the software at all. Don't talk nonsense from people who don't understand the law!