Both of these appear to return and log the same thing. Does it matter which is used? The first example is what's shown on the documentation.
var rawCalendar1 = UrlFetchApp.fetch("https://example.com/blog/events.ics");
Logger.log(rawCalendar1.getContentText());
var rawCalendar2 = UrlFetchApp.fetch("https://example.com/blog/events.ics");
Logger.log(rawCalendar2);
Return type for UrlFetchApp.fetch() is HttpResponse. In your example, you can call several methods on rawCalendar1 to inspect the returned value.
See https://developers.google.com/apps-script/reference/url-fetch/http-response
getContentText() converts the contents of HttpResponse to type 'string'. Likewise, Logger.log() casts what is between the brackets to 'string', which is essentially the same as calling getContentText() on it.