Sql-server – Why does UPDLOCK cause SELECTs to hang (lock)

I've got a select in SQL SERVER that locks the whole table.

Here's the setup script (make sure you don't overwrite anything)

USE [master]
GO

IF EXISTS(SELECT 1 FROM sys.databases d WHERE d.name = 'LockingTestDB')
DROP DATABASE LockingTestDB
GO

CREATE DATABASE LockingTestDB
GO

USE [LockingTestDB]
GO
IF EXISTS(SELECT 1 FROM sys.tables t WHERE t.name = 'LockingTestTable')
  DROP TABLE LockingTestTable
GO

CREATE TABLE LockingTestTable (
  Id int IDENTITY(1, 1),
  Name varchar(100),
  PRIMARY KEY CLUSTERED (Id)
)
GO

INSERT INTO LockingTestTable(Name) VALUES ('1')
INSERT INTO LockingTestTable(Name) VALUES ('2')
GO

Open a new query window and run the following transaction (which has a wait in it):

USE [LockingTestDB]
GO

BEGIN TRANSACTION
  SELECT * FROM LockingTestTable t WITH (UPDLOCK, ROWLOCK) WHERE t.Name = '1'
  WAITFOR DELAY '00:01:00'

COMMIT TRANSACTION
--ROLLBACK
GO

USE [master]
GO

And another one that will run (make sure they run at the same time):

USE [LockingTestDB]
GO

SELECT * FROM LockingTestTable t WITH (UPDLOCK, ROWLOCK) WHERE t.Name = '2'

USE [master]
GO

You'll notice the second query will be blocked by the first one. Stop the first query and execute the ROLLBACK and the second will complete.

Why is this happening?

PS: Adding a non-clustered index (with full coverage) over Name will fix it:

USE [LockingTestDB]
GO

CREATE NONCLUSTERED INDEX [IX_Name] ON [dbo].[LockingTestTable] 
(
  [Name] ASC
)
INCLUDE ( [Id]) WITH (STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
GO

Again why?