Good managers should focus on taking the best decisions they can with the available information. Sure if they have a tech background, some of that information is easier to process if technical, but good decisions rely on much more than just what is good in the opinion of the tech lead.
If a manager starts analyzing the technical information in front of them without the background to do so, they are missing the point. They should rely on the opinion of their more technical counterparts when the information is technical.
Yet, the opposite is also true, if a technical background person becomes manager and doesn't trust their accounting, finance, marketing counter part, then they wouldn't be a very good manager either.
The above assumes that the manager has a more general role and that decisions on technical topics isn't their only job. If yes, of course a technical background should be required.
If the manager simply does what the tech lead think is the best decision then the tech lead should be managing instead. If the manager makes technical decisions without knowing tech then he should be fired for incompetency.
If a manager starts analyzing the technical information in front of them without the background to do so, they are missing the point. They should rely on the opinion of their more technical counterparts when the information is technical.
Yet, the opposite is also true, if a technical background person becomes manager and doesn't trust their accounting, finance, marketing counter part, then they wouldn't be a very good manager either.
The above assumes that the manager has a more general role and that decisions on technical topics isn't their only job. If yes, of course a technical background should be required.