Truncation error creating clustered index on schema-bound view
The underlying table has an INT primary key column, so I was going to
  make the view's clustered index based on that.


Here's what Microsoft says about Create Indexed Views:


  Creating a unique clustered index on a view improves query performance
  because the view is stored in the database in the same way a table
  with a clustered index is stored.


Since a clustered index is composed by data rows themselves your assumption that "the only column in the index is an int" is incorrect for, even though only one column was listed on the DDL, the clustered index view shall contain all columns under the hood. If it was a Nonclustered index, then only the listed columns would compose the index.

With the DDL you provided I was able to run some lab tests and the following chart from SSMS shall ilustrate my point: 



As you can see, the view has pretty much the same size of the table. And before the index was created the view wouldn't even show on the chart. If it was formed only by the int column as you thought, it would have a much smaller size.

That info along with the contribution of SMor about the limitation of HASHBYTES Arguments for SQL Server 2008:


  For SQL Server 2014 (12.x) and earlier, allowed input values are
  limited to 8000 bytes.


In my lab I generated some data that was greater than 8000 bytes, but since I'm running a SQL Server 2019 instance, the DDL executed without any error. You can verify if you have any values that would exceed that limit with the following query:

SELECT COUNT(1)
FROM [dbo].[Events]
WHERE DATALENGTH([EventTitle]) &gt; 8000
    OR DATALENGTH([EventContent]) &gt; 8000;