OP, I do feel mean as these are heartfelt decisions and no one wants to be thought of pretentious. However, what we name our children takes place in the context of wider society so it's worth taking passing note of what others genuinely feel.
By 'try-hard' I think people mean 'pretentious'. That you've deliberately chosen an 'out there' name, something 'de trop' (I mean, come on, it's Latin!) in order to bestow a certain class. This of course may not be your intention at all. But it's what people think. Very Modern Parents: "Hello, please meet my son Catallus, and my daughter Boudicca...." You get the picture. In fact I have two friends who have daughters called Boudicca.
I say this as someone with Tendencies myself. I have been overruled by my husband over several names (and he's a Latin scholar and self-avowed poncey bastard), including Vita, Hedy (I came on here to be told it was truly HIDEOUS 
)
But although Cato itself may be underused (if used at all) the style of the name is actually ubiquitous in certain pockets. Where I live almost every boy child to middle class parents is called a two-syllable name ending in 'o'.
My issue with Cato as a name is that it will have been likely picked at random, with no ties to family (I may be wrong though) and society. To sound ostentatiously 'different' and 'cool'. Again, I bear these things in mind myself. They are not crimes as such, but I'm glad my husband can knock some sense into me sometimes.
Plus, I just can't stop thinking of Bert Kwouk.
I found naming my first daughter easy -- a Spanish name from our immediate family (we both have Spanish grandparents) that is also used in English and doesn't have pronunciation/writing issues.
But I found choosing a name for my other daughter (having her in weeks) extremely hard. Since the rest of my Spanish family were saddled with names ranging from Amparo, Soledad, Solita, Dolores etc, we didn't want to go down that route and have chosen a simpler name. It bothers me a bit that it doesn't have a family connection but I gotta call her something!
Some people won't like it -- you can't please all the people all the time.
Ultimately you have to be the same, possibly consider people's reactions but in the end go with your gut. And children have a way of growing into the most outlandish names.
And yes, groan at some of the most popular names. It's like living in an episode of Upstairs Downstairs with the girls or some Italian picaresque novel with the boys.