Under that definition, almost all rental residences in the US are investment property, and thus would be banned under the proposal.
Consider a friend of mine who owns two houses. If he lives in one, the other will be "investment property" if he rents it a significant fraction of the year and thus banned. He can't move back and forth to avoid that because there are only 12 months in the year and it takes at least 8 months (per house) to satisfy the "twice as often" requirement.
The only way out is for him to leave the second house vacant the vast majority of the year. That pretty much defeats the purpose of owning a rental and it means that someone who'd want to rent is out of luck.
What is a rental property if not an investment property? You are renting with the explicit goal of getting more returns (rent/equity/appreciation) than your costs.
Owning property for the purpose of renting it has serious negative effects on communities and society. Communities thrive when people live in them and value them, not when random people come for a few days, abuse the commons, and leave for somewhere else. If not banned, I'm all in favor of heavy regulation and taxation of investment properties, with a maximum number allocated as a percentage of the available housing. If renting becomes unpopular, people will actually have to sell and free up inventory, dropping prices.
