doc: security: rephrase introduction to security standards

Rewords the introductory text to improve grammar, flow, and clarity. The
updated text better explains the shift

Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>

Author: kartben

doc/security/standards/index.rst

@@ -3,18 +3,14 @@
 Security standards and Zephyr
 #############################
 
-For a long period organizations were, more or less, left responsible to deal
-with cyber security on their own. This included how to assess the scale and impact
-of the problem and who to properly respond it.
+Historically, organizations managed cybersecurity independently, defining their own assessment and
+response protocols. Today, governments are increasingly regulating this area through new mandates
+and security standards. These standards define specific guidelines and compliance requirements for
+connected products.
 
-Now, governments started looking how to regulate it and several regulations
-and enforcements are rapidly emerging, and consequently, security standards. These
-standards provide guidelines and outline requirements that products have to follow
-to achieve compliance.
-
-This section aims to identify and assess which Zephyr project components are impacted
-by security standards requirements and provide the right information to enable
-organizations developing certifiable products using Zephyr project.
+This section evaluates the implications of these security standards for the Zephyr project itself,
+as well as downstream product developers. The goal is to provide developers with the information
+needed to build certifiable, compliant products using Zephyr.
 
 .. toctree::
    :maxdepth: 1