I'm pretty sure the idea that drawing a line somewhat arbitrarily implies there shouldn't be a line is a straw man. Who is arguing this? The quote from the article advocates for more stringent morals--that beings that aren't fully human should be given similar moral weight as humans. It also suggests, more broadly, that we should reconsider both where these lines are drawn and if they should really be lines instead of gradients. But I see no indication that the lines should become less restrictive or any trend toward barbarism.