Good luck trying that. Most people probably avoid legal battles because it will involve more costs, thus more money lost. Blockchain.info/Blockchain.com also do have terms and conditions, which they will use in their defense.

You have to be very sure that Blockchain wallet stole your funds and have extra funds to fight them in court.
[/quote]

Welp, you would need:
1) A lawyer willing to take such cases on a contingency (payment-on-success) basis; and
2) Money for court costs (very rough estimate, $1,000-2,000).

Depending on the T&Cs and laws of the jurisdiction where you file, it is possible that you would receive a money judgment against you if your claim is entirely frivolous.

But if it's NOT -- then people really shouldn't be assuming that private corporations can steal their assets with no recourse.

Lest you think I'm just blowing smoke here: I happen to BE an attorney willing to take such cases on a contingency basis.  It looks like an area with a lot of need to me, and I can't stand the idea of companies committing theft through incompetence.