In my signature if I put a pharmacy website next to regular website link, will that devalue the regular website link? Or it doesn't matter
No, i don't think so. Bad neighbours refers to bad linking partners. You should avoid those. For example if some site that is being penalized by google or got adult content can be bad neighbour.
It doesn't matter. Bad neighborhood is related to spammy sites liking to each other. DigitalPoint is not a bad neighborhood