I haven't noticed this (I'm also very new), however, I thought of a spin you could put on that type of claim. It's safe to assume most "full time" agents don't have income from another job, meaning they *need* to represent buyers and sellers and close deals to pay their bills and feed their families. You (like me) don't *need* real estate income to survive; you're choosing to do it because you have an interest and you're looking to better yourself long-term.
If a potential client came to you and questioned your ability to represent them because you're supposedly not as serious as a full-timer, you convey to them that you don't need their business to put food on the table; you get a paycheck from your job regardless. You're offering services because you ARE a professional and you want to provide a great service.
Further, frequently I hear about peoples' bad experiences with agents, claiming they felt like their agent pressured or advised them to do something which they felt wasn't in their best interests, but would get the agent's commission paid quicker. Again, you can explain to them that you have no incentive to do that, because you don't *need* to get their commission to survive.
That ended up being a bit more wordy than I originally intended, but I think the idea is there. What do you think?