Presenting a statement that ‘both sides do it’ is a thin version of a false equivalency argument. The con of the false equivalency is also at the root of the ‘butwhattaboutyourguy’ comeback. The fact is that political faults are rarely equivalent, and even when they are, is it rational to defend your guy for doing a bad thing on the basis that somebody else’s guy did an equally bad thing in the past?

No. That defense is nothing more than a willingness to degrade the standards of morality and ethics on which civilization is maintained.

The butwhattaboutyourguy argument is only sometimes useful to highlight hypocrisy, but the user has to have been consistently critical of the misbehavior of the characters involved in order to have any credibility. The false equivalency argument, especially stated as a broad generality, is never honest.

You never change things by fighting the existing reality.
To change something, build a new model that makes the old model obsolete.
R. Buckminster Fuller