I disagree. And if a QB can't beat out the competition then they don't deserve to play.
Both QBs should be redshirting this year. I would be shocked if either didn't. You never know with injuries but it would be incredibly tough to come in as a freshman, learn an entire pro-style offense playbook, learn to read defenses and start over more experienced QBs....
Anyway, look at USC last year in taking two of the top QBs. I think the question is whether or not a PSA is afraid of competition. If a PSA doesn't want competition and they just want guarantees of the job, they should go to a school that will do that. Sarkisian has established a competitive program. It doesn't matter who you are on the team. The best players will see the field, whether you're a senior or a true freshman. I personally love it when coaches use that philosophy. I like it even more when top-talent PSAs welcome competition. If a PSA at any position was wavering on a school because they were scared of the competition with the depth in front of them, is that really the type of PSA you would want on your team?
All too quickly a position of supposed depth can be decimated by injuries. Especially at QB, you just never know when your number will be called, but if you are skilled and you have a great work ethic you will probably see the field.