Aluminum oxide (aka aluminum 'rust') forms a very hard layer, which prevents further corrosion (to a large extent). This is one big advantage of aluminum.

Normally the aluminum mesh in this case is not likely to be damaged often, so I am skeptical of the hardware person's advice.

It is something to consider though in case your water is very salty and acidic, always wet, and/or in contact with other metals (potential galvanic action).

Probably you are using fresh water and not fertilizing at extremely high levels, your soil is not always sopping wet, and the container is not metal...

Personally, I am using fiberglass screen in the bottom of my pots just because it's easier to work with (scissors and bare hands vs cutters).

Take some time to research further and be confident in your decision to not ruin your future strawberry enjoyment. =)

Basis: Extensive experience in specifying metals for indoor/outdoor use in extremely harsh environments.