On the Uselessness of Hypocrisy Arguments
As I said, I get the appeal of hypocrisy arguments. Getting someone to change their mind about substantive issues is tough work. A dedicated pro-lifer is hardly going to be upset if you tell them that Trump is awful because he wants to overturn Roe v Wade. Hypocrisy arguments, on the other hand, seem to leverage the beliefs your opponents have already committed to, in order to hoist them by their own petard. Plus, it's satisfying to believe that your opponents are unprincipled dimwits, whose attacks on your side are just psychological projections of their own flaws.
Nevertheless, hypocrisy arguments don't work. They don't work, first, because it's always possible to find some reason that the two situations being compared are different. Consider the private email servers. If you are bringing to the table a background assumption that Hillary clinton is a fundamentally untrustworthy person, someone who is scheming and unprincipled who doesn't actually care about America and its safety, then hearing that she used a private email server is going to sound pretty bad. How can we trust her not to be doing nefarious, or at least negligent, things with it? Lock her up! Meanwhile, if you bring to the table a general attitude of trust toward Donald Trump, his use of a private server seems like no big deal. He's a businessman, not a bureaucrat, and his main virtue is that he's not flexible and not bound by the way things have always been done. At worst, you might feel like it's a bit careless (if only because it gives liberals a chance to wail about hypocrisy), but he'll probably get his internet security all settled soon enough.
Hypocrisy arguments also come across as insincere. Consider the email issue again. Left-leaning people just spent a whole campaign insisting that Clinton's private server was not a big deal. So when a liberal turns around and tries to use conservative outrage over Clinton's emails as the basis for a hypocrisy charge, a conservative hearer will (reasonably) think "hey, you never cared about emails before. You're only bringing up Trump's emails because you think it's some sort of gotcha." Yes, the crux of a hypocrisy argument is the inconsistency. But it's hard to get an argument off the ground when you're demonstrating that inconsistency by getting worked up about something you don't care about substantively.
Or, think of it this way: when was the last time you were convinced by a hypocrisy argument coming from the other side of the political aisle? For most of us, it's probably been a while. And I can hear you saying: "I would totally accept a valid hypocrisy argument if one were presented to me! It's just that my opponents, in addition to being hypocrites themselves, also seem to only make terrible hypocrisy arguments that are based on spurious claims and unfair comparisons. What a bunch of nincompoops!" Fair enough. But that's exactly what they say about your hypocrisy arguments. And that's why hypocrisy arguments are not the silver bullet everyone seems to think they are.
Hypocrisy arguments rarely sway the other side. They mostly serve as a way for people on the same side to commiserate about what a bunch of nitwits the other side is. If that's your goal in making a hypocrisy argument, then carry on. But don't assume it's going to do more than that.