Parsers are not always used to belittle others over insignificant dips in DPS. Parsers are used to calculate all readouts of damage, how much damage is being done during certain phases or the course of a fight, and all sorts of objective information that provide further insight to how an encounter went. They are used to gauge where players are in regards to the amount of damage they do, and provide evidence on whether those numbers are fine or could be improved on. If someone has a parser and abuses it to harass others, we already have the means to deal with those people. Should SE implement an official parser, there would arguably be little difference in how parser abuse would be handled.
Despite the fact that tools can be abused, the fact remains that the benefits outweigh the negatives, especially against embellished claims how parsers are always used to belittle and exclude people over minimal DPS dips.