During my short time in retail sales, the number one rule was sell what you have on the shelf. I'm sure he doesn't have "bleach" on the shelf.
As
@Jimrahbe pointed out, bleach is just another name in the industry for chlorine. In it's natural state, chlorine is a gas. Many large commercial pools actually use gas injection systems to chlorinate their pools. Now, to change chlorine into something we can use at home it needs to be bound to something to turn it into a solid. The "somethings" that are commonly used are stabilizer (also known as CYA), calcium, lithium, or --- get this water. When it's water it geoes by several names - Liquid Chlorine, Liquid Shock or in household use bleach.
Now, as you pointed out, bleach for household use now has many additives to make your laundry whiter, brighter and easy to pour.
So, back to the pool store. Most pool store employees learn on the job or through seminars taught by chemical salesmen. So, bad information is handed down from employee to trainee and the chemical salesmen teach them to push high profit items. This is especially true in large chain stores where employees are paid commission and managers jobs are based on how much product flows out the door.
Are there good pool stores out there, yes! But, most of them are in the "sun" states where a family can own a small store and operate it 12 months a year, give good service and make a profit.
In the rest of the country you mainly have a high school/college kid who has about an hour training testing your water and telling you what to buy to add to your water.
Unfortunately the pool industry has evolved into sales by scare tactics, misdirection, misinformation and marketing hype. Go in to the store and tell them your TA is low and they are going to sell you baking soda in a fancy package at four times the cost of WalMart. Do they have a right to make a profit, yes - but lets be reasonable. Heck, even their definition of "low" can many times put you on a pH roller coaster that's hard to get off of. Is that lack of knowledge or a sales technique to sell you more chemicals to control your pH????
What the pool industry does not understand is that the internet is changing the industry around them. My favorite story is about my pool light. When I bought the house with the pool along with high CYA my pool light was not working. I could get a new bulb from Amazon for $19, but heck I'm part of that immediate gratification society as much as the next guy. I went down to the local pool store and there was the same bulb, $39. I talked with the manager. I didn't want them to match the price, they have to keep the lights on - just be a little more reasonable. The manager gave me two choices, take it or leave it.