Nobody out there claims that the sea shores will be under water in the next 20 years. The timeline for mass coastal inundation starts around 2100. Before then, coastal areas will cede land to the sea, but mainly in already vulnerable areas.
You ever been to Martha’s Vineyard where Obama bought his house? Many areas have massive dunes and hills, it’s not really a low lying island. Same as California. It’s not like they bought property on Key Largo.
Further,The imminent danger may not exist for everyone’s backyard today, but the imminent danger will come at different times for everyone. In the Pacific Ocean it’s already happening, in some areas it may be invasion of diseases carrying insects.
The idea that a liberal buying a house on a beach disproves or sheds doubt on climate change is absurd.