If any country censoring Tor, such as Iran or China, decided to host bridge relays, won't they be able to figure out where Tor users are and then could take action?
They can learn the IP addresses of Tor users that connect to their bridge relays. How easily they can identify a single person, find their location, and take disciplinary action probably depends on the country.
For example, if the Chinese government or its allies decided to run Meek bridges, they could find the IP addresses of Chinese Tor users and eventually identify and possibly arrest these Tor users.
It's not enough to just run a bridge, you also need to convince people to use it, either by having them enter the bridge details manually into the Tor client, or having it added to and distributed by BridgeDB. I don't think BridgeDB distributes meek bridges, but it does distribute obfs4 bridges.
Does the Tor Project protect Tor users in countries which censor Tor from this?
The Tor Project will remove bridges from BridgeDB if it finds that they are run maliciously, and as far as I know countries have been more interested in blocking Tor usage than identifying Tor users. But in general, if anyone runs a malicious Tor bridge (whether they're some government or not), they will learn the IP addresses of connecting Tor users. Bridges are more useful for evading network-level censorship than preventing anyone from learning that you're using Tor.