I'm prepared to agree on that... "abandonware" is not the same as publicdomain. Freeware, Shareware and Commersial titles from sites like Back2Roots are free to download as the people behind the site have worked sometimes very hard to get licenses to offer it for download but that doesn't meen the one downloading them have the right to sell the games (reading B2R's policy it clearly sais "Don't redistribute our file collection without express, written permission." and "You are not allowed to redistribute any of the licensed software without permission.").
Sure Doomy might have a CD full with PD titles and licensed Freeware, Shareware and perhaps even Commercial titles that allows for him to sell it at his own profit for all I know. I'm just pointing out that just because some software is Freeware, Shareware or concidered "abandonware" and available online doesn't automaticly meen you can download it and then sell it.