In early July, the Tezos foundation ran a fundraiser to fund the project's development (R&D, Bizdev, etc.). At the time it did not have funding (or very little). Its current treasury comes from that fundraiser.

It is an "ICO" because in exchange of your donation, the foundation will recommend a token allocation for you in the genesis block. Nothing prevents anyone to create a "concurrent" genesis block with different allocations though. It's just that the chances are people are going to follow the one the foundation recommends.

So, in that sense... it's an ICO. Although not quite like an ERC20 token sale.

They have $200M because people donated. The ICO is described as a fundraiser, not an investment, because it reduces liability and opportunity for government intervention. In exchange for "donation" you get XTZ. Presumably, you expect that XTZ to grow in value to make a net profit.

The upshot is that its a word that is synonymous with investment, but requires less responsibility. On the flipside, they could disappear and your are out of luck because the government won't regulate donations as carefully as securities.