I consistently do two-ish phone interviews or on-site interviews a week. I'd say 2 hours is a little on the high side for average time per candidate (probably around 1.5 hours), but it does happen. I am sometimes called in to do tiebreaker interviews (before or even after on-site interviews), or requested for particular candidates. I occasionally help other groups (capacity engineering, software engineering, operations engineering) with their interviews on top of my usual load. I've flown overseas for people who can't easily get US visitor visas. I'm in the top 5 interviewers by quantity for the role (which isn't too hard, admittedly), and in the top few percent of the company (I even got some ice cream as thanks!).
In addition to interviews, I also spend an hour a week in a recruiting meeting trying to improve our recruiting process (including giving feedback to our interviewers on how to improve their interviewing and feedback). And I've done non-interview recruiting at universities (manning booths at career fairs, mentoring at hackathons) and conferences (at Velocity, SCALE, Surge, PyCon just in the last year).
My feeling about spending 4-6 hours a week on interviewing and recruiting activities is that it is some of the most valuable work I can be doing. Avoiding a false positive - ensuring we maintain a consistent high bar - is going to save people in my group (and others in the company) potentially hundreds of hours. Making a great hire is going to add thousands of hours of productivity to my group and the company.
And we're a small enough group (and even a small enough company for the non-PE hires I've helped with) that I can easily keep track of the people I've helped hire and it is supremely fulfilling.