Filling it with water is obviously not the objective. Wonder what it's about

The objective is humor.

cleaning it? this is likely a laundry or vegetable basket

Easier to carry it home this way since it doesn’t get as heavy as similarly-sized containers. Science.

maybe washing it?

Probably humor. Are we sure it’s even a real photo?

But I can picture running the water to clear out contamination, and maybe you’ll see anything in the basket. Or maybe running it to get cold water and the basket is just because

When my kids were little, we had a sizeable collection of inflatable sprinkler toys. Then one time I was setting up our water park just before a cookout ….. as I turned one on, I heard a loud pop and the toy immediately clogged. Apparently the hose had something trying to live in it and its mud/nest burst out into the toy, ruining it. This is one reason it to drink from a hose

Probably using it to filter out any chunks.

He’s trying to find the best water filter

Joke’s on you assholes. There is no water spilled.