Proper way to use formatting in tabular with siunitx

Question

My question is similar to siunitx: aligning numbers by decimal points in tables doesn't work for bolded or italicized numbers , except I would like to apply formatting to a row or a specific cell, not a whole column. I have not been able to applying the suggested answers to make siunitx interpret the bold or color macros.

The section 9.4 of the siunitx package documentation says that

using the e-TeX protected mechanism is the recommended course of action to prevent expansion of macros in table cells

but I still don't know how to properly do that. I tried to apply what is proposed here with no success:

\documentclass{article}
\usepackage{booktabs}
\usepackage{etoolbox}
\robustify\bfseries
\usepackage{siunitx,xcolor}
\sisetup{detect-weight=true, detect-inline-weight=text, locale = FR}
\begin{document}
\begin{tabular}{l S S}
        \toprule
        \textbf{Foo} & \textbf{Col1} & \textbf{Col2}  \
        \midrule
        foo1 & 11.1 & 11.1\
        foo2 & 222.2 & 222.2\
        \textbf{foo3}  & \textbf{3.333} & \textbf{3.333}\
        foo4  & 4 & 4\
        foo5  & 555.55 & \textcolor{gray}{555.55}\
        foo6 & 6.00 & 6.00\
        \bottomrule
\end{tabular}
\end{document}

Thanks for your help.

Answer 1

Thanks to @Joseph Wright comment I made it using \bfseries instead of \textbf, and \color instead of \textcolor (with no brackets at all):

\documentclass{article}
\usepackage{booktabs}
\usepackage{siunitx,xcolor}
\sisetup{detect-weight=true, detect-inline-weight=text, locale = FR}
\begin{document}
\begin{tabular}{l S S}
        \toprule
        \textbf{Foo} & \textbf{Col1} & \textbf{Col2}  \
        \midrule
        foo1 & 11.1 & 11.1\
        foo2 & 222.2 & 222.2\
        \textbf{foo3}  & \bfseries 3.333 & \bfseries 3.333\
        foo4  & 4 & 4\
        foo5  & 555.55 & \color{gray} 555.55\
        foo6 & 6.00 & 6.00\
        \bottomrule
\end{tabular}
\end{document}