So you remove or alter copyright notices from developers without paying them, for both free and paid add-ons? So you break the terms of your license agreement?
Support is continued over a period of time. You pay more for warranty for your home appliances, you pay continued costs for support within software, hardware, leasing, and throughout all aspects of life. It costs money to keep giving support, so after a period of time you're expected to fund that, an initial period often comes with your license.
And of course you have to sign up to a website to make your payment and get an add-on. By law, we're expected to ask you to provide certain information for taxation and record-keeping purposes, not to mention it also helps tailor a better experience for you, the customer. You sign up when you buy Windows, or buy a product from Amazon, or want to buy advertising within Google's network, or when you want to order some furniture or some clothes from Ted Baker. And if you mean free add-ons, well, the developer is really doing you a favour, a few moments of your precious time to sign up isn't much to ask for.
I don't know how you can expect sympathy when you have none for the time of developers and openly admit to breaking license agreements, depriving developers of money that you'd be expected to pay as per a legal agreement you agree to when downloading or using the product.