Yes, absolutely ruling out a personal home as an investment makes no sense. It's YMMV.
Using the colloquial meaning of investment -- I put some money into something with the hope that over time it will go up in value or provide some kind of financial return -- then a personal home can definitely be an investment.
OP, if a personal home can never be an investment, then what do you call this hypothetical situation?:
Joe decides his community is up and coming, has great long term growth and job potential, and he thinks real estate where he lives will likely go up in value. He buys a house for $100,000 (puts $20k down), moves in, and 15 years later it is worth $400,000. He sells it and pockets a profit of $300,000 (minus transaction costs, maintenance costs along the way, etc.).