You did not read the text below the core integrity checker:
Note. This is not a malware scanner but an integrity checker which is a completely different thing, if you want to check if your site is generating malicious code then use the malware scan tool.
Considering that you posted this I will assume that you do not know what an integrity check is, I suggest you to read this article [1] and this [2] too, and compare it with what a malware scanner is with the information here [3]; let me know if you need more information.
And please do not be rude, there are several plugins in the market that you can install for free to complement the tools available in the Sucuri plugin, if you want to have a better software with smart malware detection I suggest you to try our Antivirus [4] or CloudProxy [5] which are two of our premium services, they are not free as this plugin but if you really want a malware scanner then they are for you; refer to our website [6] for more information.
[1] https://en.wikipedia.org/wiki/File_integrity_monitoring
[2] https://en.wikipedia.org/wiki/Data_integrity
[3] https://en.wikipedia.org/wiki/Antivirus_software
[4] https://sucuri.net/website-antivirus/
[5] https://sucuri.net/website-firewall/
[5] https://sucuri.net/
