To some, this is a contentious point while to others it seems entirely logical.
I must tell you that I've witnessed this very assertion as it has been raised more times in the last few days than I can count.
Before I get into any more juicy bits regarding this topic, I wonder if you wouldn't mind popping over and reading a blog post I wrote in August, 2007 titled "On-Demand SaaS Vendors Able to Secure Assets Better than Customers?"
Come to think of it, you can read the follow-on post to that one which clearly indicated my point when Salesforce.com and Monster.com (you know, those so-called "Cloud" providers) were breached.
Forgot about those breaches, did you? Oh, that must have been because they were SaaS providers and not Cloud providers at the time. Gotcha.
As you read these posts, first do so within the context of what we've come to know as software as a service (SaaS.) Then kindly re-read it and substitute 'SaaS' with 'Cloud,' won't you?
I have more, but I'll wait till you're done.