> Hence, algorithm implies that it provides correct answers within the parameters of the problem.

And so they always do. The problem that an algorithm solves is defined by the algorithm itself. The purpose of a system is what it does[0].

Algorithms are useful to solve problems for us - the trick is always in making sure that the problem the algorithm solves is the one we want.

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[0] - https://en.wikipedia.org/wiki/The_purpose_of_a_system_is_wha...

That's a bingo.

Disagree. We see this phenomena all the time: Right solution, bad input data. Right solution, wrong problem. Worlds turned to grey goo by replicators working to some technically correct algorithm.

These will never give the right solution, only something close.

The definition of algorithm is wider than you think. As your parent poster noted, "greedy algorithms" exist (as do many other algorithms which provide suboptimal answers). You can easily verify this by googling.