The vast majority of work that makes it into all of the major Linux Distributions is funded by corporate interests and it is often difficult to tell what their motivation is. It is not out of the goodness of their hearts.
The common wisdom is that most Linux distributions are more secure than Windows largely because their user bases are much smaller. 77% of desktop and laptop computers run Windows vs 2% running Linux. They are a much smaller target for hackers. Linux users also are typically more tech savvy than Windows users... and there are other reasons for security issues. But there is less accountability with those developing Linux distributions and they tend to take longer to react to newly discovered threats.
But the major security threats to most people are not their desktops and laptops, but their phones and tablets. Samsung and Google provide the longest support for their products... 5 to 7 years. But other manufacturers such as Motorola provide only 2 years and some provide security updates only as long as the model phone or tablet is being produced. Phones, which most people use for financial purposes and all sorts of communication are woefully insecure.
But of course, fishing scams are the primary way people's personal information is stolen and even the best of us fall for this type of crap on occasion.
This discussion could go on and on... Personally, I use Windows, Linux distributions my phones and Apple devices for what they are best at. No operating system is completely bulletproof.
Sorry--Not the case.
Don't forget that while Windows has the majority of the user desktop market, Linux pretty much rules the datacenter and backends of many commercial/govt enterprises. The data Linux runs on/protects is MUCH more valuable than anything a desktop user may have.
While the user base may play a small part, it is not in fact the reason why Linux is more secure. It is more secure due to initial base design.
Windows started off as an app sitting on top of DOS. DOS itself was a single-user OS as it was designed before networking was a large concern, and before the basic end user even knew about networking (yes, networking existed, but was largely confined to educational institutions and commercial applications).
Due to the desire, or need, to maintain backward compatibility MS continued to build on that initial design philosophy. I'm not saying it was wrong, or bad (at the time), but it is what happened.
Linux, OTOH, was designed later on after multi-user systems were much more common. Given this different initial environment, basic design is a LOT different, with most decisions based on the multi-user aspect of the OS.
That is the main reason Linux is more secure. It's still not totally secure, but it is more secure.