Well it is in primary setting of the mod therefore it is part of a mod. Any alternative settings are well alternative. As said again. If I join the server I have no control of any alternative settings. And the I don't want to install modpack and them go through each mod config to make sure they want bite me.
Ah yes, the power of defaults hard at work again. See, the setting is there because some people do change configs now and then. It's a option that is there mostly, I suppose, because they spawn entities, and that can cause lag. And then there are seeds that literally spawn entities, like the squid seed or the slime seed.
But then again, a wise coder takes these sort of things into account. Maybe the setting exists because they knew it's cool enough to warrant leaving on, but can be a issue in the end so they added the setting because, like a wise coder, they saw a problem and made a solution that doesn't really cause any issues in the end.
But the power of defaults is why people bemoan DartCraft(well, that, and Anchoring, but that's another discussion) yet sing the praises of TiC for adding less balanced things that do what DartCraft does as a paragon of balance, and why when DartCraft allows you to pick up machines, chests, and a handful of other blocks, it's evil and bad and unbalanced, and when TE3 does it as cheap as DartCraft used to(and DartCraft has long since balanced that mechanic) it is the best mod ever despite all but ripping off DartCraft with that mechanic in the first place.
But the whole DartCraft vs The World issue is another discussion, but that bit sure as hell applies here. IMO, anyway.