There is a good reason. The private yachts and jets ferry the world’s elite to climate change conferences. Climate change conferences reduce global warming.
It's a reason, but is it a good one? It depends on the way you look at it.
I think it's possible that carbon footprint could become a (somewhat narcissistic) metric that individuals use to gauge and signal their self-worth (in addition to other vanity metrics).
On the one hand, claiming that your individual actions have reduced carbon emissions for a wide population could result in genuine behavioural changes and environmental improvements (even if it turns out to be difficult to calculate attribution to specific people).
On the other hand, if only individuals with high net worth are able to travel by private jet/yacht (a reality already, to be honest), and they are able to use their existing wealth to offset their environmental damage enough to come out net-positive in terms of ROI (image + reputation being leveraged into financial reward), then what has been created is a tiered class system without social mobility where long-distance travel is only available to a small number of people.
From that line of thinking I'd suggest that environmental cost produced per person should be a key metric to keep in mind, regardless of offsets.
There's simply no good reason for yachts and private jets to be exempt.