Atheists can be a funny bunch. It's very common for them to insult Christian apologists rather than argue their case. The three common objections are that said apologist is under qualified/not qualified at all to speak on the topic, that they are, or have been, responsible for some kind of immorality, or even that they're just in it for the money.
When someone launches an ad hominem attack, I find a particularly effective strategy is to show how little such accusations matter. Even if demonstrably true (which they very rarely are) accusations launched against apologists say more about the apologist than the beliefs they hold. What really matters is the arguments they put forward.
Atheistic apologists, especially the popular ones, have a lot of dubious things that can be pinned on them. From the simple foul language some of them use even in the middle of a formal debate to scamming their followers out of large amounts of money, the dirt you could dig up on them is enough to fill a quarry. But as Christians, we don't need to dig up that dirt. We can afford to pretend each individual atheist does not exist. Now, there are some arguments that are unique, or close to unique, to individual atheists, but even those arguments can be attacked directly. For example, I don't need to dig up dirt on Richard Dawkins, I just need to show that his argument that the human eye is "badly designed" only works if he thinks human beings should be color blind, and only able to see while underwater. Who cares if Dawkins is in it for the money? Why does it matter that he's an infanticidal maniac who is curious about cannibalism? His arguments would be wrong if he committed to a life of poverty and vegetarianism while simultaneously donating 90% of his income to pro-life charities.
As a general rule, if your go-to strategy is to attack the character of your opponent, you are awful at arguing. Ultimately, there is no greater a compliment you can give an apologist than "you've made such a compelling case that rather than attack it, I'm going to attack you".