TSQL and Table Lock on one row
Any queries that read the table WITH (NOLOCK) or with READ UNCOMMITTED isolation level will proceed despite your WITH (TABLOCKX).

More info about lock modes can be found here:
https://technet.microsoft.com/en-us/library/ms175519(v=sql.105).aspx

Personally I'd say that if you have queries reading from the table WITH (NOLOCK) then they should fully anticipate that they will get bad results so blocking those reads wouldn't be a priority. If your those queries need to return data that is actually correct then they should not use NOLOCK. https://sqlstudies.com/2015/03/18/why-not-nolock/