I work in tech but not for the big guys, I think it's fair for two reasons
First, tech interviews are inherently flawed, where your past experience doesn't matter, so any time you go on a job hunt you have to practice your interviewing skills. On top of all the practice, you have to do, you normally do 5 – 7 interviews with one company to get an offer. Together they can last a full working day. Earlier it was the employee's market and normally after interviewing with 3 – 4 companies you would get one offer. After the layoffs, it has become an employer's market where even the small to mid companies have raised the bar by a lot. Now getting an offer usually takes interviewing with at least 8 – 10 companies. I used to take personal days off for the interview. I can't do that now, I don't even get 8 personal days.
Secondly, tech companies know full well, that when they asked employees to go on interview sprees with them, they have to do that with full-time jobs. Yet there hasn't been any effort from recruiters and tech leadership to change the process and make it efficient. So when they make other companies' employees steal time from them, they should be well aware that their employees will do the same.
I personally was not in favor of doing that but I have no choice now, so guilt is pointless I guess. Now I spread those interviews over the week and do them within the company's time