Criticisms about online programming contests and algorithms-focused interviews

True. Trying to predict candidate's performance in such complex activity like programming by using a single source of info (competition results) is as effective as predicting if someone will be a good football player just by looking how fast he can run. Sure, it will affect the performance but it's not the only competence required. And not the most important either.

That's why multi-angle approach is a must. Not to mention well defined competencies the company is looking for, which is often also a big problem.

I think this is entirely correct. In general, the best sort of environment for coding is in a supportive environment where your colleagues are willing to discuss issues with you, give hints or assistance or review your work.

Coding shouldn't be done in a hurry, but with care. That's IMO.